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>> [Music kucheza]

2
00:00:03,332 --> 00:00:06,200

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00:00:06,200 --> 00:00:09,590
>> DAN AMRMENDARIZ: Kila mtu,
kuwakaribisha kwa CS50 semina hiyo,

4
00:00:09,590 --> 00:00:11,690
iOS App Maendeleo na Swift.

5
00:00:11,690 --> 00:00:15,690
Mimi nina Dan Armendáriz, na mimi nina preceptor
ya sayansi ya kompyuta hapa katika Harvard.

6
00:00:15,690 --> 00:00:21,510
>> Na saa ijayo ni kwenda kuwa
ziara kimbunga cha mambo mengi

7
00:00:21,510 --> 00:00:25,160
kuhusu mada hii kama tunaweza fit.

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00:00:25,160 --> 00:00:29,170
Nami baada yote ya chanzo kanuni
kwamba utaona leo online.

9
00:00:29,170 --> 00:00:31,990
Tunaweza kuwa na uwezo wa
kweli kwenda juu ya kila kitu

10
00:00:31,990 --> 00:00:34,810
kwamba mimi nina kwamba mimi nina
kuonyesha katika saa hii.

11
00:00:34,810 --> 00:00:37,580
Lakini angalau hopefully kupitia
maoni ya chanzo kanuni,

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00:00:37,580 --> 00:00:40,830
wewe utakuwa na uwezo wa kujaribu kufikiri nini
hasa kinachotokea kwa mambo hayo

13
00:00:40,830 --> 00:00:42,950
kwamba hatuna kabisa kupata.

14
00:00:42,950 --> 00:00:46,970
>> Kwa ujumla, muundo wa
Majadiliano ya leo itakuwa kama ifuatavyo.

15
00:00:46,970 --> 00:00:52,820
Tutaweza kuanza nje kufanya baadhi ya msingi
syntax kwa lugha Swift,

16
00:00:52,820 --> 00:00:56,290
kwenda katika baadhi ya juu zaidi
syntax ya lugha Swift.

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00:00:56,290 --> 00:00:59,560
Kwa sababu lugha
ni kweli kisasa na

18
00:00:59,560 --> 00:01:02,110
ina mengi ya ngazi ya juu
makala, mambo ambayo tuna si

19
00:01:02,110 --> 00:01:06,600
kuonekana katika C katika CS50, au
hata baadhi ya lugha nyingine

20
00:01:06,600 --> 00:01:09,310
kwamba tumekuwa kuanza
kutumia katika CS50 kama PHP,

21
00:01:09,310 --> 00:01:12,670
hivyo mimi ni kwenda kuwa na kujaribu
kuanzisha pia baadhi ya mada ambazo

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00:01:12,670 --> 00:01:18,580
ni kuhusiana na lugha ngazi za juu
kwamba unaweza kuona katika kina katika CS50,

23
00:01:18,580 --> 00:01:21,380
lakini utaona katika baadaye
sayansi ya kompyuta madarasa.

24
00:01:21,380 --> 00:01:25,290
Hivyo ni kwenda kuwa
lenye msongamano mkubwa saa.

25
00:01:25,290 --> 00:01:28,897
Na tafadhali jisikie huru basi mimi
kujua kama una maswali yoyote.

26
00:01:28,897 --> 00:01:30,730
Hivyo kama wewe ni nia
kwa kufanya maendeleo

27
00:01:30,730 --> 00:01:34,442
pamoja Swift, au kweli
yoyote iOS programu ya maendeleo,

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00:01:34,442 --> 00:01:35,900
kuna wanandoa wa mahitaji.

29
00:01:35,900 --> 00:01:39,940
Awali ya yote, una kutumia
Mac, mbio katika mifano

30
00:01:39,940 --> 00:01:43,880
kwamba sisi ni kwenda kuwa na kutumia leo,
toleo la kipya cha OS

31
00:01:43,880 --> 00:01:46,580
X. Katika kesi hiyo, mimi nina mbio X 10.5.

32
00:01:46,580 --> 00:01:48,600
Unaweza kuwa mbio 10.11 kama unataka.

33
00:01:48,600 --> 00:01:52,430
Lakini kila kitu ambacho wewe ni kwenda
ona ni kuwashirikisha Xcode 7 na baadaye,

34
00:01:52,430 --> 00:01:56,271
ambayo ina toleo la karibuni
ya Swift, ambayo ni Mwepesi 2.0.

35
00:01:56,271 --> 00:01:58,270
Hii ni kweli pretty
muhimu tofauti.

36
00:01:58,270 --> 00:02:01,510
Mengi ya syntax ina
iliyopita pretty kiasi kikubwa

37
00:02:01,510 --> 00:02:05,890
katika baadhi ya kesi kutoka Swift 1.0,
ambayo ilitolewa mwaka jana,

38
00:02:05,890 --> 00:02:08,514
kwa Swift 2.0, ambayo
tu akatoka hii kuanguka.

39
00:02:08,514 --> 00:02:09,889
Hivyo sisi ni kwenda kuonyesha Swift 2.0.

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00:02:09,889 --> 00:02:13,020
Mambo mengi ambayo
wewe kutafuta online

41
00:02:13,020 --> 00:02:18,040
wakati wewe ni kujaribu kupata nyongeza
taarifa kuhusu aina ya mambo,

42
00:02:18,040 --> 00:02:20,710
unaweza kutaka kupanga
kutafuta Swift 2

43
00:02:20,710 --> 00:02:24,950
badala ya wazi tu umri wa Swift kufanya
uhakika kwamba kupata syntax sahihi.

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00:02:24,950 --> 00:02:26,920
>> Kwa kweli, hii ni kwa ujumla kweli.

45
00:02:26,920 --> 00:02:31,210
Kuna kiasi ya haraka ya maendeleo
kinachotokea katika lugha Swift

46
00:02:31,210 --> 00:02:35,110
tangu wakati huo Apple iliyotolewa yake, nadhani
nini, imekuwa ni kidogo zaidi ya mwaka

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00:02:35,110 --> 00:02:36,370
sasa.

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00:02:36,370 --> 00:02:39,080
Na mambo yamebadilika
kasi wakati huo.

49
00:02:39,080 --> 00:02:42,160
Na hivyo si kuwa frustrated
kama, wakati wewe ni kuangalia kuzunguka

50
00:02:42,160 --> 00:02:48,310
kwa mada juu ya Swift au jinsi ya kutekeleza
kitu kwa kutumia baadhi mfano kificho

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00:02:48,310 --> 00:02:51,210
au kitu ambacho hana
kweli kazi juu ya Swift 2.0.

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00:02:51,210 --> 00:02:53,790
Kuhakikisha wewe ni kuangalia
mahsusi kwa ajili ya toleo kwamba

53
00:02:53,790 --> 00:02:58,690
kujaribu kupunguza madhara ya tofauti
matoleo na wale aina ya mambo.

54
00:02:58,690 --> 00:03:02,470
>> Nitajaribu kumweka nje baadhi tu ya mambo
ambayo ni tofauti na matoleo ya zamani.

55
00:03:02,470 --> 00:03:03,970
Lakini ni kitu cha kuangalia nje kwa.

56
00:03:03,970 --> 00:03:06,770
Hiyo pengine ni kwenda kuwa
moja ya maumivu ya kichwa kubwa

57
00:03:06,770 --> 00:03:11,010
kwamba utakuwa na kwa Swift ni kutafuta
mfano kificho kwamba ni wakubwa, hata tu

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00:03:11,010 --> 00:03:14,050
na miezi michache, kujaribu kutumia
hivyo katika zaidi ya kisasa ya mradi wako.

59
00:03:14,050 --> 00:03:15,430
Na ni haki tu haifanyi kazi.

60
00:03:15,430 --> 00:03:18,530
Wewe ni kupata makosa compiler, syntax
makosa, kila aina ya mambo mambo.

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00:03:18,530 --> 00:03:21,580
Hivyo tu kuwa na subira na
hiyo, na wewe hopefully

62
00:03:21,580 --> 00:03:24,200
wana uzoefu mzuri nzuri
kwa ujumla Swift.

63
00:03:24,200 --> 00:03:28,430
>> Sasa unaweza kweli join-- na natumaini
sisi kweli bado wana hii year-- hii

64
00:03:28,430 --> 00:03:30,910
CS 50 ya Apple programu
timu ya maendeleo, ambayo

65
00:03:30,910 --> 00:03:34,680
itawawezesha kufunga programu yoyote
ambayo wewe kujenga juu yako iOS.

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00:03:34,680 --> 00:03:39,190
Hivyo kuchukua kuangalia URL hii ikiwa
una nia ya kufanya hivyo.

67
00:03:39,190 --> 00:03:41,450
>> Hivyo michache tu ya
mambo kuhusu Swift yenyewe.

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00:03:41,450 --> 00:03:43,580
Ni lugha ulioandaliwa.

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Lakini utaona kwamba baadhi
ya sifa ya kuwa sisi kutumia

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00:03:45,870 --> 00:03:50,650
kuruhusu ni kutumika pia katika kidogo
kama kufasiriwa kwa njia vilevile.

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00:03:50,650 --> 00:03:56,350
>> Mengi ya syntax ni alikopa
kutoka C. Ni msingi na kuandikwa katika C.

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Na hivyo tutaona kwamba
kuna mengi ya takeaways

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00:04:00,400 --> 00:04:04,450
kutokana na elimu yako zilizopo
kutoka C kwamba tunaweza bandari ya Swift.

74
00:04:04,450 --> 00:04:07,290
>> Lakini kuna mambo ambayo
kufanya hivyo tofauti sana na C.

75
00:04:07,290 --> 00:04:08,860
Ni nguvu sana typed.

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00:04:08,860 --> 00:04:10,380
Kuna usimamizi wa kumbukumbu moja kwa moja.

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00:04:10,380 --> 00:04:13,170
Wewe si kwenda na
kutumia malloc au bure mahali popote.

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00:04:13,170 --> 00:04:15,110
Ni iliyoundwa kwa ajili ujumla.

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00:04:15,110 --> 00:04:19,480
Hivyo kwa maneno mengine, unaweza kutumia katika
kila aina ya mazingira, kutoka Apple Watch

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00:04:19,480 --> 00:04:26,290
kwa iPhone njia yote hadi OS X, na
hata baadhi ya watumishi, hata baadhi ya scripting.

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00:04:26,290 --> 00:04:28,400
Lakini tutaweza kuona kwamba
msaada kwa ajili ya scripting

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00:04:28,400 --> 00:04:31,360
sio kabisa huko bado kama
ni katika lugha nyingine.

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00:04:31,360 --> 00:04:34,930
Hivyo uwezekano mkubwa wewe utakuwa na kutumia
hii kwa ajili tu ya maendeleo

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00:04:34,930 --> 00:04:37,060
juu ya Mac yako au iPhone yako.

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00:04:37,060 --> 00:04:40,150
>> Na ina mengi ya makala kisasa.

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00:04:40,150 --> 00:04:43,380
Na mengi ya mambo haya ni mambo ambayo
tunakwenda kujaribu kushughulikia leo,

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00:04:43,380 --> 00:04:47,590
lakini pia mada yetu kwamba kusema ukweli,
tunaweza kujishughulisha kozi nzima.

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00:04:47,590 --> 00:04:50,140
Kwa kweli, CS 51, ambayo ni
inayotolewa muhula ujao,

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00:04:50,140 --> 00:04:53,990
inalenga mengi juu ya mada hizi
kwamba ni ilivyoelezwa hapo chini.

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00:04:53,990 --> 00:04:56,781
Hivyo unaweza kutumia muhula mzima
kuelewa mambo haya.

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00:04:56,781 --> 00:04:58,530
Lakini sisi ni kwenda kujaribu
kupata njia yao

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00:04:58,530 --> 00:05:00,800
angalau kutosha kwamba
anaweza kuelewa nini

93
00:05:00,800 --> 00:05:03,700
kinachoendelea wakati ukiangalia
katika mpango Swift

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00:05:03,700 --> 00:05:07,310
na kuwa na uwezo wa hack njia yako
kwa njia hiyo kwa mradi wa mwisho.

95
00:05:07,310 --> 00:05:10,780
>> Sasa moja ya njia bora kwamba unaweza
kupata maelezo ya ziada juu ya hili

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00:05:10,780 --> 00:05:14,700
ni kusema ukweli tu kupitia Apple
zinazotolewa nyaraka kwa ajili ya Swift.

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00:05:14,700 --> 00:05:16,930
Kuna mengi ya APIs
ambayo inapatikana.

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Na hii ni nzuri nyumbani msingi kwa ajili yenu
kwa kuangalia, mambo maalum kwamba

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00:05:21,170 --> 00:05:23,020
wanataka kufanya na API kuwashirikisha iOS.

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00:05:23,020 --> 00:05:26,350
Kama unataka kutumia kamera kwa
mfano, unaweza kuanza kuangalia hapa,

101
00:05:26,350 --> 00:05:32,540
na pia kutumia Google na Stack
Kufurika kama wewe ungekuwa kawaida.

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00:05:32,540 --> 00:05:36,670
>> Maswali yoyote juu ya hii
kabla ya sisi kuruka haki katika?

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00:05:36,670 --> 00:05:37,880
Sawa.

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00:05:37,880 --> 00:05:38,700
Hebu hoja juu.

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00:05:38,700 --> 00:05:42,620
>> Hivyo kwanza, nina
idadi ya mafaili mfano.

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00:05:42,620 --> 00:05:46,040
Na mimi nina kwenda kujaribu hatua
njia yao kiasi haraka.

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00:05:46,040 --> 00:05:49,190
Faili hili Hello World kwa Swift.

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00:05:49,190 --> 00:05:51,050
Ni rahisi sana.

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00:05:51,050 --> 00:05:54,360
Kuna maoni njia zaidi
kuliko kuna kanuni halisi.

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00:05:54,360 --> 00:05:57,100
Taarifa kificho halisi ni katika
chini sana kwenye mstari 14.

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00:05:57,100 --> 00:05:57,980
Inasema magazeti.

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00:05:57,980 --> 00:05:59,820
Na kisha ni kazi ya wito.

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00:05:59,820 --> 00:06:03,010
Sisi ni kupita ndani yake
string kuitwa Habari cs50.

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00:06:03,010 --> 00:06:04,750
Taarifa kwamba hakuna semicolons.

115
00:06:04,750 --> 00:06:07,010
Taarifa kwamba hakuna int kuu.

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00:06:07,010 --> 00:06:10,392
Kuna hakuna wa
cruft kwamba tulikuwa na C.

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Wakati sisi ni kutumia Swift kwa njia hii,
ambayo imeandikwa tu katika faili maandishi

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na kuhifadhiwa kwenye kompyuta yangu, kisha
Siwezi kukusanya ni na kukimbia nayo.

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>> Taarifa kwamba hapa mimi nina
si kwa kutumia CS50 IDE.

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00:06:20,920 --> 00:06:24,460
Hii akubali kwamba mimi ni
mbio na kwamba mimi nina juu ya OS X,

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na kwamba mimi Xcode tayari imewekwa
juu ya mashine hii ili kwa hili

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00:06:27,870 --> 00:06:29,080
kwa kweli kazi.

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00:06:29,080 --> 00:06:33,349
Lakini hii ni kawaida ya maandishi ya faili
tuweze kisha kukusanya na hariri.

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00:06:33,349 --> 00:06:34,890
Basi hebu angalia jinsi hii kweli kazi.

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00:06:34,890 --> 00:06:37,430
Nini kama nataka kukusanya ni?

126
00:06:37,430 --> 00:06:40,450
swiftc 1.swift.

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00:06:40,450 --> 00:06:42,960
Baada ya muda au mbili, ni
utaona kwamba tuna sasa

128
00:06:42,960 --> 00:06:45,360
ulioandaliwa hii katika faili inayoitwa 1.

129
00:06:45,360 --> 00:06:51,090
Na sasa tuna kuchapishwa CS50 yetu,
Hello World yetu maombi badala.

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00:06:51,090 --> 00:06:54,690
>> Taarifa ya jambo moja nyingine kama
vizuri ni kwamba by default,

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00:06:54,690 --> 00:07:00,090
hatukuwa na pembejeo
a / n na magazeti mstari mpya.

132
00:07:00,090 --> 00:07:05,315
By default, magazeti kazi katika
Swift magazeti mstari mpya kwa ajili yenu.

133
00:07:05,315 --> 00:07:09,284
Unaweza kupita hiari ziada
parameter kuwaambia kuwa si kufanya hivyo.

134
00:07:09,284 --> 00:07:10,950
Lakini Google kwa maelezo zaidi juu ya hilo.

135
00:07:10,950 --> 00:07:13,450
By default, itakuwa kufanya mstari magazeti.

136
00:07:13,450 --> 00:07:16,420
>> Haki wote, hivyo hebu hoja juu ya
kisha kwa baadhi ya mambo mengine.

137
00:07:16,420 --> 00:07:18,620
Hivyo ni jinsi gani sisi kweli kufafanua vigezo?

138
00:07:18,620 --> 00:07:21,960
Tunaweza kufanya hivyo kwa kutumia
moja ya njia mbili.

139
00:07:21,960 --> 00:07:26,122
Na moja kwamba mimi nataka kukuambia
kuhusu kwanza ni huu ufafanuzi let.

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00:07:26,122 --> 00:07:27,830
Na hii ni muhimu
kwa sababu kwa ufanisi

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00:07:27,830 --> 00:07:30,240
nini sisi ni kufanya ni kufafanua mara kwa mara.

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00:07:30,240 --> 00:07:34,010
Tunaenda kuunda kutofautiana,
au tuseme mara kwa mara kuitwa jina,

143
00:07:34,010 --> 00:07:38,200
kutoa yake baadhi data-- katika
kesi hiyo, kamba Dan.

144
00:07:38,200 --> 00:07:40,630
Lakini kwa kutumia let hii
keyword, tunasema

145
00:07:40,630 --> 00:07:43,860
kwamba hii kutofautiana au
tena constant-- aitwaye

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00:07:43,860 --> 00:07:46,220
jina ni kamwe kwenda kubadilishwa.

147
00:07:46,220 --> 00:07:50,120
Ni kwenda kuwa hayabadiliki katika
muda wa mpango huu

148
00:07:50,120 --> 00:07:53,100
au katika
muda wa mazingira

149
00:07:53,100 --> 00:07:55,390
kuwa kwamba kutofautiana inapatikana.

150
00:07:55,390 --> 00:08:00,096
>> Hii ni kweli ni muhimu kwamba wakati
una baadhi ya takwimu ambazo siyo

151
00:08:00,096 --> 00:08:02,970
kwenda na mabadiliko katika mpango wako,
na utaona aina ya mifano

152
00:08:02,970 --> 00:08:06,790
kuhusu wakati tunataka kutumia
basi dhidi syntax mengine,

153
00:08:06,790 --> 00:08:11,040
ni muhimu kwamba wewe kutumia basi
popote iwezekanavyo kwa sababu notifies hii

154
00:08:11,040 --> 00:08:13,740
lugha kuwa ni
si kwenda kubadilishwa,

155
00:08:13,740 --> 00:08:16,590
na ni kweli anaweza kufanya
mengi ya optimizations

156
00:08:16,590 --> 00:08:19,560
kuboresha kasi na
usalama wa programu yako.

157
00:08:19,560 --> 00:08:24,480
Na kwa usalama, I mean, si lazima
ni ajali na mambo makosa

158
00:08:24,480 --> 00:08:27,910
ili tuweze kuwa
wamezoea kuona katika C.

159
00:08:27,910 --> 00:08:32,460
>> Basi tunaweza kutumia kamba nyongeza katika kitabu
kurejelea hii ndani ya kamba.

160
00:08:32,460 --> 00:08:35,200
Ili tuweze kuona katika hii
magazeti line, magazeti hodi,

161
00:08:35,200 --> 00:08:38,950
na kisha kwa kutumia backslash wazi parens,
na kisha jina la kutofautiana yangu,

162
00:08:38,950 --> 00:08:41,809
katika hii mara kwa mara kesi,
karibu mabano.

163
00:08:41,809 --> 00:08:46,400
Mimi kimsingi kisha kuweka
yaliyomo ya hii jina kutofautiana kuitwa

164
00:08:46,400 --> 00:08:50,240
ndani ya kamba na kisha
uchapishaji matokeo huko.

165
00:08:50,240 --> 00:08:54,070
>> Kuna moja mabadiliko mengine na faili hili
ambayo ni kwamba mimi, juu sana,

166
00:08:54,070 --> 00:08:57,340
kuweka katika mstari shebang, ambayo
kimsingi tu bayana

167
00:08:57,340 --> 00:09:00,180
kwamba mimi nataka kutumia
Swift mkalimani, ambayo

168
00:09:00,180 --> 00:09:04,190
maana yake ni kwamba mimi tena kuwa na
kukusanya mpango huu hasa.

169
00:09:04,190 --> 00:09:06,567
Siwezi kukimbia tu ni kama Muswada yake mwenyewe.

170
00:09:06,567 --> 00:09:09,400
Lakini hii ni, katika kesi hii, nyuma ya
pazia kuwa ulioandaliwa na kisha

171
00:09:09,400 --> 00:09:10,030
kuwa kukimbia.

172
00:09:10,030 --> 00:09:13,540
Ni tu asiyeonekana kwetu.

173
00:09:13,540 --> 00:09:15,880
>> Haki wote, hivyo hebu kuondoka.

174
00:09:15,880 --> 00:09:19,650
Hivyo kuna kidogo ya hila
kwamba ilitokea tu kabla.

175
00:09:19,650 --> 00:09:23,230
Mimi ilionyesha kuwa mimi
aliweza kuainisha mara kwa mara.

176
00:09:23,230 --> 00:09:25,490
Na mimi naweza kutoa baadhi data ya kufanya hivyo.

177
00:09:25,490 --> 00:09:29,240
Lakini katika kesi hii, taarifa kwamba sikuwa
kweli bayana aina ya data

178
00:09:29,240 --> 00:09:29,820
kuwa ni.

179
00:09:29,820 --> 00:09:32,780
Na hiyo ndiyo sababu
compiler, Swift Unaweza

180
00:09:32,780 --> 00:09:36,910
kudai aina ya data kwa kuzingatia tu
juu ya data kwamba mimi kuweka ndani yake.

181
00:09:36,910 --> 00:09:41,760
Kwa sababu anajua kwamba kwa kufanya tathmini ya hii
kutofautiana haki hapa, hii haki data

182
00:09:41,760 --> 00:09:43,370
hapa, ni anajua kwamba ni kamba.

183
00:09:43,370 --> 00:09:48,690
Na hivyo jina hili mara kwa mara ni kwa hiyo
kwenda kuwa kamba vilevile.

184
00:09:48,690 --> 00:09:52,730
>> Lakini tunaweza pia kuwa wazi
kuhusu aina hiyo ni

185
00:09:52,730 --> 00:09:55,790
sisi ni kwenda kutumia kwa
constants au vigezo

186
00:09:55,790 --> 00:10:01,590
kwa kutumia syntax hii instead--
basi jina matumbo Kamba sawa na

187
00:10:01,590 --> 00:10:05,530
Dan, ambayo katika kesi hii ina maana tuko
kwenda kufafanua mara kwa mara kuitwa jina.

188
00:10:05,530 --> 00:10:07,150
Ni kwenda kuwa ya aina Kamba.

189
00:10:07,150 --> 00:10:10,550
Na thamani ni kwenda kuwa Dan.

190
00:10:10,550 --> 00:10:12,550
Sasa njia nyingine ambazo
tunaweza kujenga variables--

191
00:10:12,550 --> 00:10:15,549
na hizi ni vigezo mutable, ambayo
ina maana kwamba sisi ni, kwa kweli, kwenda

192
00:10:15,549 --> 00:10:19,670
kubadili yaliyomo yao wakati mwingine
katika muda wa mazingira

193
00:10:19,670 --> 00:10:23,890
kwamba kuwa kutofautiana ni defined-- sisi
kutumia var keyword badala ya basi.

194
00:10:23,890 --> 00:10:27,400
Lakini tena, kwa default, isipokuwa wewe kujua
kwamba unahitaji kuendesha data kwamba,

195
00:10:27,400 --> 00:10:30,510
kujaribu kutumia basi kwa
utendaji maboresho.

196
00:10:30,510 --> 00:10:33,740
>> Katika kesi hiyo, naweza kisha
kutaja aina ya data

197
00:10:33,740 --> 00:10:37,650
kwamba tunatarajia kuwa ndani ya
kutofautiana hii mpya iitwayo studio.

198
00:10:37,650 --> 00:10:38,800
Ni kwenda kuwa kamba.

199
00:10:38,800 --> 00:10:43,030
Na tunakwenda kisha concatenate
masharti mawili kwa pamoja, kamba hodi,

200
00:10:43,030 --> 00:10:48,070
na kamba inawakilishwa na
kutofautiana, au tuseme jina mara kwa mara.

201
00:10:48,070 --> 00:10:50,660
>> Hivyo hii ni nzuri kwa sababu hii
ni kiasi fulani PHP kama katika kwamba sisi

202
00:10:50,660 --> 00:10:52,250
kuwa rahisi sana kamba concatenation.

203
00:10:52,250 --> 00:10:56,350
Hatuna moja kwa moja
kutumia aina yoyote ya usimamizi wa kumbukumbu

204
00:10:56,350 --> 00:11:00,580
kuongeza ukubwa na kufanya
aina yoyote ya mambo funny huko.

205
00:11:00,580 --> 00:11:05,040
Hii kazi kama tunataka kweli kutarajia.

206
00:11:05,040 --> 00:11:09,370
>> Haki zote, maswali yoyote juu ya hili?

207
00:11:09,370 --> 00:11:12,520
>> Sasa sababu nyingine ambazo
tunahitaji una uwezo

208
00:11:12,520 --> 00:11:15,490
kuwa na uwezo wa kufafanua nini
aina ya data vigezo ni

209
00:11:15,490 --> 00:11:18,170
ni kwa sababu wakati mwingine hatuna
wanataka initialize vigezo

210
00:11:18,170 --> 00:11:21,080
pamoja na baadhi ya data katika
hatua ya ufafanuzi.

211
00:11:21,080 --> 00:11:23,500
Hivyo katika kesi hii, hebu sema
kuwa nataka kuanza inputting

212
00:11:23,500 --> 00:11:25,040
baadhi darasa katika kitabu daraja.

213
00:11:25,040 --> 00:11:27,530
Naam Najua kwamba moja ya
vigezo kwamba mimi nataka kuwa

214
00:11:27,530 --> 00:11:30,280
ni kwenda kuwa daraja mutable.

215
00:11:30,280 --> 00:11:33,010
Na tunajua pia kwamba sisi
unataka kuwa integer.

216
00:11:33,010 --> 00:11:36,030
Lakini labda tunafanya bado
na kwamba daraja kutosha.

217
00:11:36,030 --> 00:11:39,570
>> Katika Swift, una
kufafanua aina ya data

218
00:11:39,570 --> 00:11:44,000
kwamba ni kuhusishwa na
kutofautiana au basi mara kwa mara

219
00:11:44,000 --> 00:11:47,840
kabla unaweza kweli
kutumia kwamba kutofautiana.

220
00:11:47,840 --> 00:11:51,170
Kwa sababu ni nguvu typed,
una kujiunga aina

221
00:11:51,170 --> 00:11:52,890
na vigezo hivi.

222
00:11:52,890 --> 00:11:56,120
>> Hivyo katika kesi hii, kama nimekuwa vizuri
initialized kwanza kwa baadhi ya thamani,

223
00:11:56,120 --> 00:12:00,520
kisha mimi haja ya kuwaambia nini Swift
Natarajia aina data kuwa.

224
00:12:00,520 --> 00:12:02,650
Na itakuja kubakia
takwimu ambazo aina moja

225
00:12:02,650 --> 00:12:05,780
kipindi chote cha historia ya mpango huu.

226
00:12:05,780 --> 00:12:10,050
>> Sasa unaweza kujaribiwa kwa haraka kama
I have umba hii kutofautiana daraja

227
00:12:10,050 --> 00:12:13,530
na zinazotolewa ni
integer ya 100, sasa kama mimi

228
00:12:13,530 --> 00:12:18,540
wanataka kujaribu concatenate
kamba na kwamba integer,

229
00:12:18,540 --> 00:12:21,610
kujaribiwa bado kutumia
kwamba kamba concatenation operator

230
00:12:21,610 --> 00:12:24,500
kama tulivyofanya mistari michache tu kabla.

231
00:12:24,500 --> 00:12:26,460
Lakini kwa bahati mbaya,
hii itakuwa kweli si

232
00:12:26,460 --> 00:12:29,270
kazi, kwa sababu wewe ni
kimsingi kufanya

233
00:12:29,270 --> 00:12:32,380
operesheni juu ya aina mbili tofauti.

234
00:12:32,380 --> 00:12:36,856
>> Sasa hii ni tofauti sana na wengine
lugha kama PHP ambayo ni kweli

235
00:12:36,856 --> 00:12:38,480
loosey goosey na aina yao ya aina.

236
00:12:38,480 --> 00:12:40,030
Wao ni tu kama, yeah,
chochote, Sijali.

237
00:12:40,030 --> 00:12:42,710
Nipe tu aina moja, na
labda mimi itabidi kufanya jambo sahihi.

238
00:12:42,710 --> 00:12:46,060
>> Katika kesi hiyo, Swift ni
kali sana kuhusu aina

239
00:12:46,060 --> 00:12:47,350
kwamba wewe ni kushughulika na.

240
00:12:47,350 --> 00:12:50,700
Alama hii summation
au concatenation operator

241
00:12:50,700 --> 00:12:54,400
ina kimsingi michache ya
chaguzi mbalimbali iwezekanavyo.

242
00:12:54,400 --> 00:12:56,970
Unaweza kufanya summation
kwa integers, au wewe

243
00:12:56,970 --> 00:13:00,870
anaweza kufanya kamba concatenation, na
labda baadhi ya mambo mengine pia.

244
00:13:00,870 --> 00:13:05,550
Lakini kama hiyo operator haitambui
kile ni upande wake,

245
00:13:05,550 --> 00:13:10,452
au tuseme mchanganyiko wa wale
aina mbili, ni si nini ni tegemeo,

246
00:13:10,452 --> 00:13:11,910
kisha itakuja kusababisha kushindwa.

247
00:13:11,910 --> 00:13:16,690
>> Hivyo katika kesi hii, ni nini maana
kuwa na kamba pamoja na integer?

248
00:13:16,690 --> 00:13:18,880
Vizuri katika mazingira ya
hili, sisi pengine wanataka

249
00:13:18,880 --> 00:13:21,990
kufanya operesheni kamba concatenation.

250
00:13:21,990 --> 00:13:26,420
Lakini bila shaka kompyuta
hana kwamba aina ya mazingira.

251
00:13:26,420 --> 00:13:29,950
Na hivyo tunahitaji kutoa
habari kwamba ziada

252
00:13:29,950 --> 00:13:32,390
basi ni kujua nini
ni kwamba tunataka kufanya.

253
00:13:32,390 --> 00:13:36,860
>> Hivyo kwa maneno mengine, ukweli
kwamba Swift sana typed

254
00:13:36,860 --> 00:13:39,520
ina maana una kufanya
kidogo ya kazi ya ziada

255
00:13:39,520 --> 00:13:42,100
kupata kazi
njia ambayo wewe unataka.

256
00:13:42,100 --> 00:13:43,710
Lakini matokeo yake, ni salama.

257
00:13:43,710 --> 00:13:46,290
Na mara moja una kuchukua
maanani wale aina,

258
00:13:46,290 --> 00:13:49,300
mambo kusema ukweli tu kuanza
kufanya kazi pretty vizuri.

259
00:13:49,300 --> 00:13:52,520
>> Hivyo katika kesi hii, sisi kisha ingekuwa
kufanya kamba concatenation

260
00:13:52,520 --> 00:13:56,040
na waziwazi akitoa
integer kwa kamba

261
00:13:56,040 --> 00:13:58,490
kwa wrapping katika hii
mji mkuu S Kamba kazi,

262
00:13:58,490 --> 00:14:03,510
na kisha kwa kutumia kamba concatenation
operator kurekebisha studio yetu kutofautiana,

263
00:14:03,510 --> 00:14:06,280
na kisha magazeti ya nje.

264
00:14:06,280 --> 00:14:08,420
>> Hadi sasa, hivyo nzuri?

265
00:14:08,420 --> 00:14:12,020
Sawa, hebu kuondoka.

266
00:14:12,020 --> 00:14:16,300
>> Sasa kuna aina ya data
aina kwamba tunaweza kutumia katika Swift.

267
00:14:16,300 --> 00:14:21,620
Kama wewe kuwa desturi ya,
tunaweza kujenga safu mutable.

268
00:14:21,620 --> 00:14:26,140
Na kwamba safu Unaweza tu
vyenye aina moja.

269
00:14:26,140 --> 00:14:30,360
>> Hivyo katika kesi hii, sisi ni kwenda kujenga
arrays mutable ya integers, ambayo

270
00:14:30,360 --> 00:14:34,800
sisi kuwaita darasa, na sisi kuwa na uwezo
kuhifadhi kwamba katika mabano mraba huu

271
00:14:34,800 --> 00:14:38,650
muundo kama umefanya mzima wamezoea
kwa katika aina mbalimbali za lugha nyingine.

272
00:14:38,650 --> 00:14:41,150
Lakini taarifa kwamba hapa tuko
kufafanua mambo kadhaa.

273
00:14:41,150 --> 00:14:45,350
darasa ni kutofautiana mutable
sisi si kutumia let Keyword.

274
00:14:45,350 --> 00:14:49,620
Hivyo kwamba maana tunaweza kisha kurekebisha
yaliyomo ya safu hii.

275
00:14:49,620 --> 00:14:53,420
Ni ya aina Array Int,
na tunaweza kujua kwamba

276
00:14:53,420 --> 00:14:56,260
kulingana na haya mabano mraba hapa.

277
00:14:56,260 --> 00:14:58,930
>> Sasa ni moja ya mambo mazuri
kuhusu hili ni kwamba sisi

278
00:14:58,930 --> 00:15:02,310
wanapata mengi ya
Taarifa za ziada

279
00:15:02,310 --> 00:15:07,110
kuhusu safu kwa kutumia tu
baadhi rahisi dot nukuu.

280
00:15:07,110 --> 00:15:10,500
Hivyo kwa mfano,
grades.count hutoa kwetu

281
00:15:10,500 --> 00:15:14,820
idadi ya vitu ambazo zipo katika kwamba
safu, ambayo tunaweza kisha kupata pretty

282
00:15:14,820 --> 00:15:19,090
urahisi tu kwa kutumia kwamba dot nukuu.

283
00:15:19,090 --> 00:15:21,830
>> Kama unataka kuongeza ziada
vitu na safu hii,

284
00:15:21,830 --> 00:15:27,220
huwezi kufanya PHP style
ambapo wewe tu wazi kufafanua,

285
00:15:27,220 --> 00:15:30,910
katika ripoti iliyotolewa, baadhi thamani
kuwa unataka kuingiza.

286
00:15:30,910 --> 00:15:37,210
Badala yake, matumizi append
Njia katika aina safu

287
00:15:37,210 --> 00:15:40,920
append kwamba bidhaa, 95, kwa orodha hii.

288
00:15:40,920 --> 00:15:45,990
>> Hivyo sasa safu hii ina zifuatazo
contents-- 100, 0, 90, 85.

289
00:15:45,990 --> 00:15:49,270
Na sasa tumekuwa umeongezewa
95 kwa kuwa vilevile.

290
00:15:49,270 --> 00:15:51,830
>> Kuna njia nyingine
tunaweza append mambo.

291
00:15:51,830 --> 00:15:55,030
Unaweza kweli kutumia
summation operator,

292
00:15:55,030 --> 00:15:59,200
ambayo itakuwa kutafsiriwa kama
safu append operesheni.

293
00:15:59,200 --> 00:16:04,680
Na unaweza kisha append nyingine
safu, ambayo ina maandishi ni 70 na 80,

294
00:16:04,680 --> 00:16:05,560
kwa kuwa safu.

295
00:16:05,560 --> 00:16:08,250
Hivyo basi, tuna
yaliyomo katika kutofautiana hii

296
00:16:08,250 --> 00:16:17,220
grades-- 100, 0, 90, 85, 95, 70, na 80.

297
00:16:17,220 --> 00:16:21,850
Hii ni nzuri tu kisintaksia kidogo
sukari kwamba Swift hutoa kwetu.

298
00:16:21,850 --> 00:16:23,850
>> Hivyo kama tunataka kwa jumla
darasa, tuko labda

299
00:16:23,850 --> 00:16:27,340
atataka iterate
juu ya kila kitu katika kitanzi hii.

300
00:16:27,340 --> 00:16:32,150
Na hatuwezi kuwa, katika Swift, dhana
ya kwa kitanzi kama ungependa kutarajia.

301
00:16:32,150 --> 00:16:35,350
Lakini njia hiyo sisi zinaonyesha
mbalimbali ni tofauti kidogo.

302
00:16:35,350 --> 00:16:37,790
Hivyo katika kesi hii, kwa
kuhitimisha kila kitu, tutaweza

303
00:16:37,790 --> 00:16:40,650
kwenda kujenga muda
kutofautiana kuitwa kiasi ili na sisi

304
00:16:40,650 --> 00:16:42,580
kudumisha hesabu hii.

305
00:16:42,580 --> 00:16:44,430
>> Na taarifa kwa wetu
kitanzi ujenzi hapa.

306
00:16:44,430 --> 00:16:46,820
Kwa ripoti katika 0 .. <grade.count.

307
00:16:46,820 --> 00:16:51,480

308
00:16:51,480 --> 00:16:57,390
Hivyo hii ujenzi, 0 .. <grades.count
ni operesheni mbalimbali ambapo sisi ni

309
00:16:57,390 --> 00:17:01,860
akisema kwamba sisi ni kwenda kujenga
mbalimbali ya integers kutoka 0 hadi

310
00:17:01,860 --> 00:17:05,750
kwa lakini ukiondoa grades.count.

311
00:17:05,750 --> 00:17:09,577
Hivyo hii itakuwa 0, 1, 2, 3, 4,
5, hadi hata hivyo wengi moja

312
00:17:09,577 --> 00:17:10,410
kabla grades.count.

313
00:17:10,410 --> 00:17:14,160
>> Hivyo hii ni tofauti kuliko jinsi sisi
ingekuwa kawaida kutumika kwa ajili ya mizunguko

314
00:17:14,160 --> 00:17:18,569
ambapo ingekuwa baadhi ripoti
kutofautiana, kuweka sawa na 0 mara ya kwanza,

315
00:17:18,569 --> 00:17:25,480
na kisha kuunganisha kwamba mpaka baadhi
thamani chini ya hesabu ya vitu

316
00:17:25,480 --> 00:17:27,140
katika safu hiyo.

317
00:17:27,140 --> 00:17:29,820
>> Kwa hiyo, kuna mabadiliko
kwa hiyo, kwa kweli,

318
00:17:29,820 --> 00:17:35,010
ambayo inaruhusu sisi urahisi sana
kuweka aina mbalimbali za safu.

319
00:17:35,010 --> 00:17:40,570
Kama mabadiliko haya mbalimbali ili
nukta tatu, 0 ... grade.count,

320
00:17:40,570 --> 00:17:45,120
hii inawakilisha mbalimbali 0
kwa grades.count umoja,

321
00:17:45,120 --> 00:17:49,260
kwa maana ya kuwa idadi hiyo ni pia
kisha ni pamoja na katika mbalimbali.

322
00:17:49,260 --> 00:17:52,110
>> Lakini hii ni Handy sana
maana hayo halisi,

323
00:17:52,110 --> 00:17:54,590
wakati tuna kufanya
iterations juu ya kitanzi

324
00:17:54,590 --> 00:17:59,630
kwa sababu bahati hizo sifuri indexed,
kama tumeona katika lugha zingine

325
00:17:59,630 --> 00:18:02,360
vilevile.

326
00:18:02,360 --> 00:18:05,210
Maswali yoyote juu ya hii kwa kitanzi?

327
00:18:05,210 --> 00:18:10,660
>> Hivyo kuna thabiti ufafanuzi
ya kutofautiana hii ripoti,

328
00:18:10,660 --> 00:18:14,350
thamani ambao huanza saa 0, na
inaendelea katika kila iteration ya kitanzi

329
00:18:14,350 --> 00:18:17,950
kuongezeka kwa 1 hadi hatua
ambayo ni sawa na grades.count,

330
00:18:17,950 --> 00:18:20,380
ambapo kiwango, kitanzi aborts.

331
00:18:20,380 --> 00:18:23,730
>> Taarifa kwamba katika kamba yetu
kitabu hapa,

332
00:18:23,730 --> 00:18:26,910
sisi kweli anaweza kufanya baadhi rahisi
manipulations kwa maadili hayo.

333
00:18:26,910 --> 00:18:31,230
Hivyo ripoti pamoja na 1 mapenzi kweli
kufanya summation wa thamani kwamba

334
00:18:31,230 --> 00:18:34,780
kwa sababu ripoti ni, katika
kesi hiyo, integer.

335
00:18:34,780 --> 00:18:37,810
Na katika hatua hiyo, itakuwa
kisha kuwa waongofu katika kamba

336
00:18:37,810 --> 00:18:42,230
na interpolated katika kamba hii hapa,
na kuchapishwa kama tungetarajia. .

337
00:18:42,230 --> 00:18:44,520
>> Na kitu kizuri
kuhusu arrays hapa ni

338
00:18:44,520 --> 00:18:50,730
kwamba sisi pia ni uwezo wa kuwa na
maadili kuchota na kuweka maadili

339
00:18:50,730 --> 00:18:54,080
kutumia mraba bracket nukuu kama
tumeona katika lugha zingine vilevile.

340
00:18:54,080 --> 00:18:57,130

341
00:18:57,130 --> 00:19:01,030
>> Haki wote, hivyo kutoka hapa, sisi sasa
compute kiasi yetu ya yote ya darasa letu.

342
00:19:01,030 --> 00:19:02,780
Sasa aina ya ujao
hatua mantiki itakuwa

343
00:19:02,780 --> 00:19:07,580
kufanya mgawanyo wa operesheni ya kutafuta
nje wastani wa wale wanafunzi wa darasa.

344
00:19:07,580 --> 00:19:10,150
Lakini kitu muhimu
hapa kinachotokea ambayo

345
00:19:10,150 --> 00:19:15,020
ni kwamba jumla hii ni labda integer.

346
00:19:15,020 --> 00:19:18,020
Lakini tunahitaji kufanya baadhi ya
aina ya mara mbili mgawanyiko.

347
00:19:18,020 --> 00:19:20,600
Na hii ni kwenda kuwa
muhimu sana wakati

348
00:19:20,600 --> 00:19:24,140
tunataka kufanya operesheni hii,
kwa sababu kile tunasema

349
00:19:24,140 --> 00:19:28,430
ni kwamba tunahitaji kweli
kufanya mgawanyo juu ya mbili mara mbili.

350
00:19:28,430 --> 00:19:31,370
Na tena, kwa sababu Swift
ni sana sana typed,

351
00:19:31,370 --> 00:19:36,760
ni lazima waziwazi kuweka yote ya
vitu na mara mbili kabla ya sisi kweli

352
00:19:36,760 --> 00:19:38,300
kufanya operesheni hiyo.

353
00:19:38,300 --> 00:19:40,550
>> Hivyo ili na sisi kwa
kufanya mara mbili mgawanyiko,

354
00:19:40,550 --> 00:19:43,730
siyo ya kutosha kwa ajili moja tu
ya vitu hivyo kuwa mara mbili.

355
00:19:43,730 --> 00:19:46,400
Wote wawili kuwa
mara mbili ili mwepesi

356
00:19:46,400 --> 00:19:50,860
kuwa na uhakika kwamba hii
ni nini tunataka kufanya.

357
00:19:50,860 --> 00:19:54,360
Hivyo tutakuwa na kisha kupanga typecast
Jumla ambayo tumekuwa computed juu

358
00:19:54,360 --> 00:19:58,970
na hesabu ya wanafunzi wa darasa kwa mara mbili, na
kisha kufanya kwamba operesheni na kuhifadhi

359
00:19:58,970 --> 00:20:02,390
kwamba katika kutofautiana hii mpya, au tuseme
mara kwa mara hii mpya iitwayo wastani,

360
00:20:02,390 --> 00:20:06,810
ambayo itakuwa na ni aina gani, unaweza kufikiria?

361
00:20:06,810 --> 00:20:07,587
Double, yeah.

362
00:20:07,587 --> 00:20:09,420
Hivyo katika kesi hii, sisi
hawana kutaja ni

363
00:20:09,420 --> 00:20:13,450
sababu inaweza inferred kutoka
operesheni ni aina gani ya data wastani

364
00:20:13,450 --> 00:20:14,730
itakuwa.

365
00:20:14,730 --> 00:20:19,025
Na Swift ni nzuri kwa ujumla
juu ya kuwa na uwezo wa kudai aina.

366
00:20:19,025 --> 00:20:22,116

367
00:20:22,116 --> 00:20:24,200
>> Je, unataka kuona hii
kukimbia, au naweza kusonga mbele?

368
00:20:24,200 --> 00:20:25,640
Nataka kuendelea.

369
00:20:25,640 --> 00:20:28,130
Maswali yoyote juu ya yoyote ya hili?

370
00:20:28,130 --> 00:20:28,630
Kubwa.

371
00:20:28,630 --> 00:20:31,160

372
00:20:31,160 --> 00:20:35,010
>> Sasa sisi ni kwenda kuanza kupata
nzuri stuff-- kazi kufafanua,

373
00:20:35,010 --> 00:20:39,090
na wanandoa wa aina nyingine ambazo ni
kipekee kwa Swift kwamba una si

374
00:20:39,090 --> 00:20:41,620
kuonekana katika lugha zingine
hadi hatua hii,

375
00:20:41,620 --> 00:20:46,290
lakini waliopo katika mengine
lugha ambazo unaweza kupata baadaye.

376
00:20:46,290 --> 00:20:48,210
Hivyo kwanza kama unataka
kufafanua kazi,

377
00:20:48,210 --> 00:20:52,170
unaweza kufafanua kwa neno funky
kazi, na kisha jina kazi,

378
00:20:52,170 --> 00:20:56,710
na kisha katika mabano, hoja
kwamba unataka kazi ambayo kukubali.

379
00:20:56,710 --> 00:21:00,280
Lazima hoja pia
specify-- generally--

380
00:21:00,280 --> 00:21:05,010
Lazima pia kutaja aina ya data kwamba
wao, isipokuwa wao inaweza inferred.

381
00:21:05,010 --> 00:21:07,500
Na tutaweza kuona kwamba kidogo
caveat katika kidogo tu.

382
00:21:07,500 --> 00:21:09,920
>> Hivyo katika kesi hii tuna
kazi kuitwa printGradeCount.

383
00:21:09,920 --> 00:21:12,840
Tunakwenda kukubali
kutofautiana au tuseme katika kesi hiyo,

384
00:21:12,840 --> 00:21:14,450
constant-- aitwaye gradebook.

385
00:21:14,450 --> 00:21:18,517
Na ni kwenda kuwa ya
aina safu ya integers.

386
00:21:18,517 --> 00:21:20,600
Sasa kuna kitu
hiyo ni kweli ni muhimu hapa

387
00:21:20,600 --> 00:21:21,849
kwamba mimi nataka kuelewa.

388
00:21:21,849 --> 00:21:27,560
Hiyo ni kwamba by default, hoja hizi
ambazo ni pembejeo kwa kazi hii ni

389
00:21:27,560 --> 00:21:34,380
inavyoelezwa na thabiti hebu keyword,
ambayo ina maana kwamba siwezi kurekebisha hii

390
00:21:34,380 --> 00:21:39,850
gradebook kutofautiana hapa.

391
00:21:39,850 --> 00:21:43,360
Na kwamba aina ya mantiki,
kwa sababu wewe ni kupita data katika.

392
00:21:43,360 --> 00:21:45,860
Na wewe labda hawataki
kubadilishwa kutoka chini ya wewe.

393
00:21:45,860 --> 00:21:50,800
Inawezekana kupanga kutaja
kwamba hii ni kutofautiana kwa kuweka

394
00:21:50,800 --> 00:21:52,070
var keyword hapa.

395
00:21:52,070 --> 00:21:56,832
Lakini hiyo ni gotcha kwamba tumekuwa
watu niliona wamefanya katika siku za nyuma

396
00:21:56,832 --> 00:21:59,790
ni kwamba wao kudhani kuwa itakuja
kuwa kutofautiana wakati, kwa kweli, ni

397
00:21:59,790 --> 00:22:02,640
ni mara kwa mara.

398
00:22:02,640 --> 00:22:07,340
>> Haki wote, hivyo hapa ndipo, katika kesi hii,
sisi si kubainisha aina yoyote ya kurudi.

399
00:22:07,340 --> 00:22:09,460
Tutaweza kuonyesha jinsi ya kufanya
kwamba katika muda tu.

400
00:22:09,460 --> 00:22:12,340
Lakini taarifa kwamba hapa tuna
rahisi tu kama hali hiyo.

401
00:22:12,340 --> 00:22:14,560
Kama gradebook ni
tupu, ambayo katika kesi hii

402
00:22:14,560 --> 00:22:19,310
ni tu mali ya integer hii
safu, basi sisi magazeti nje kitu.

403
00:22:19,310 --> 00:22:23,100
Vinginevyo sisi kufanya kitu kingine chochote.

404
00:22:23,100 --> 00:22:25,000
>> Pretty moja kwa moja hadi sasa nadhani.

405
00:22:25,000 --> 00:22:27,960
Lakini kuacha mimi kama una maswali yoyote.

406
00:22:27,960 --> 00:22:33,350
>> Sasa kazi hii, kwa wastani, pia inachukua
baadhi ya hoja, au tuseme moja hoja,

407
00:22:33,350 --> 00:22:37,507
ambayo ni gradebook, na wakati huu
ni kwenda na kurudi aina mbili.

408
00:22:37,507 --> 00:22:39,340
Kwa sababu ni kompyuta
wastani na ni

409
00:22:39,340 --> 00:22:45,010
kwenda kweli kurudi kwamba
wastani computed katika wito line.

410
00:22:45,010 --> 00:22:50,070
>> Katika kesi hiyo, sisi kutaja
kurudi aina baada ya mshale.

411
00:22:50,070 --> 00:22:53,260
Na hii wanaweza kujisikia
aina ya weird mara ya kwanza.

412
00:22:53,260 --> 00:22:55,610
Umefanya mzima wamezoea
kwa kuweka kurudi

413
00:22:55,610 --> 00:22:57,720
aina kabla ya jina la kazi.

414
00:22:57,720 --> 00:23:00,310
Lakini kama wewe kufikiria hii
katika suala la hisabati,

415
00:23:00,310 --> 00:23:03,320
kama wakati una hisabati
kwamba kufafanua kazi,

416
00:23:03,320 --> 00:23:06,807
una kazi pamoja na baadhi
pembejeo, na inazalisha pato.

417
00:23:06,807 --> 00:23:08,890
Na kwamba ni nini hasa
hii ni walidhani kuiga.

418
00:23:08,890 --> 00:23:12,460
Na kuna wanandoa wa lugha nyingine
ambazo zina syntax sawa pia,

419
00:23:12,460 --> 00:23:15,674
lakini pengine hata mmoja
wameweza kuona katika CS50.

420
00:23:15,674 --> 00:23:17,090
Lakini bado wala kuwa na kuchanganyikiwa kwa hilo.

421
00:23:17,090 --> 00:23:21,650
Mshale ina maana kile kinachoendelea
kurudishwa katika kesi hii.

422
00:23:21,650 --> 00:23:23,650
OK, hivyo ni jinsi ni sisi kwenda
compute wastani hili?

423
00:23:23,650 --> 00:23:25,649
Naam, kama gradebook
ni tupu, vizuri basi tuko

424
00:23:25,649 --> 00:23:30,731
kwenda na kurudi 0, ambayo labda
njia nzuri ya kutibu hii.

425
00:23:30,731 --> 00:23:32,980
Sijui, hebu kuja
nyuma na kwamba katika kidogo.

426
00:23:32,980 --> 00:23:34,688
Hii inaweza si kweli
kuwa njia nzuri

427
00:23:34,688 --> 00:23:38,310
compute wastani ikiwa
tuna gradebook tupu.

428
00:23:38,310 --> 00:23:41,260
>> Kisha tutaweza tu kufanya summation yetu.

429
00:23:41,260 --> 00:23:43,900
Taarifa kwamba hapa sisi kweli
kuwa na toleo mbadala ya

430
00:23:43,900 --> 00:23:49,190
kwa kitanzi, ambayo inaruhusu sisi iterate
zaidi ya kila kitu moja katika safu

431
00:23:49,190 --> 00:23:53,630
na mahali kila kipengele
ndani ya kutofautiana yake mwenyewe.

432
00:23:53,630 --> 00:23:56,200
Na kubainisha kwa daraja katika
gradebook, nini tunasema

433
00:23:56,200 --> 00:24:00,560
ni kwamba tunakwenda inamuunga
kujenga mara kwa mara mpya iitwayo

434
00:24:00,560 --> 00:24:05,180
Daraja kwamba ni kwenda kuwakilisha
kila kitu kipekee katika gradebook

435
00:24:05,180 --> 00:24:06,769
kila wakati kwamba kwa kitanzi iterates.

436
00:24:06,769 --> 00:24:08,560
Hivyo mara ya kwanza kwa
ni kukimbia, daraja mapenzi

437
00:24:08,560 --> 00:24:09,800
kuwa bidhaa ya kwanza katika gradebook.

438
00:24:09,800 --> 00:24:12,300
Mara ya pili utakuwa
bidhaa pili, kadhalika na kadhalika

439
00:24:12,300 --> 00:24:15,970
mpaka gradebook ina
nimechoka yenyewe ya mambo.

440
00:24:15,970 --> 00:24:20,390
Kisha sisi kuwa na uwezo wa kuhitimisha kwamba
daraja katika summation yetu kutofautiana

441
00:24:20,390 --> 00:24:22,570
na kurudi wastani wetu
kama tumeona kabla.

442
00:24:22,570 --> 00:24:25,670

443
00:24:25,670 --> 00:24:26,950
Sawa, maswali yoyote?

444
00:24:26,950 --> 00:24:27,699
Ndiyo?

445
00:24:27,699 --> 00:24:28,990
Watazamaji: Nina maswali mawili.

446
00:24:28,990 --> 00:24:33,586
Namba moja, hypothetically, unaweza
kukimbia integer juu ya hili?

447
00:24:33,586 --> 00:24:35,604
Hana na kuwa
mara mbili, ni kwamba ni sahihi?

448
00:24:35,604 --> 00:24:37,520
DAN AMRMENDARIZ: Je, unaweza
kurudia swali hilo?

449
00:24:37,520 --> 00:24:39,587
Watazamaji: Je, mimi kufanya
integer kama wastani?

450
00:24:39,587 --> 00:24:41,670
DAN AMRMENDARIZ: Je, unaweza
kufanya integer kama wastani?

451
00:24:41,670 --> 00:24:45,015
Hivyo kurudi integer
wastani badala ya mara mbili?

452
00:24:45,015 --> 00:24:48,204
>> Watazamaji: Return-- wewe
na kwamba hivi sasa hapa chini.

453
00:24:48,204 --> 00:24:49,870
DAN AMRMENDARIZ: Hapa hapa, kurudi 0.0?

454
00:24:49,870 --> 00:24:51,790
Watazamaji: Yeah, tu kurudi 0.

455
00:24:51,790 --> 00:24:56,590
Hivyo itakuwa ama
80 au 85, lakini si 85.2.

456
00:24:56,590 --> 00:24:59,465
>> DAN AMRMENDARIZ: Hivyo katika kesi hiyo,
hivyo kuna njia kadhaa tofauti

457
00:24:59,465 --> 00:25:00,090
kujibu hilo.

458
00:25:00,090 --> 00:25:02,760
Napenda kujibu yao kwa utaratibu.

459
00:25:02,760 --> 00:25:06,740
Hivyo kama mimi tu kufanya kurudi huu
0, 0 ni thamani integer.

460
00:25:06,740 --> 00:25:09,730
Na hivyo kuwa itakuwa na kusababisha
Aina ya makosa ya kesi hii

461
00:25:09,730 --> 00:25:13,210
kwa sababu ni mara mbili wanatarajia
lakini ni kisha kurejea integer.

462
00:25:13,210 --> 00:25:16,770
Kama mimi nataka kurudi integer, naweza.

463
00:25:16,770 --> 00:25:20,450
Naweza kuweka aina ya kurudi
int, kurudi 0 hapa,

464
00:25:20,450 --> 00:25:22,047
na si kufanya mara mbili mgawanyiko.

465
00:25:22,047 --> 00:25:23,880
Lakini basi tunataka kuwa
kufanya integer mgawanyiko.

466
00:25:23,880 --> 00:25:27,080
Na hivyo sisi kisha bila kupata
wastani kwamba tunataka uwezekano kutarajia.

467
00:25:27,080 --> 00:25:29,210
Lakini ndiyo tunaweza kurekebisha
aina katika njia hiyo.

468
00:25:29,210 --> 00:25:32,598
>> Watazamaji: Na pili, wewe
kuwa moja mara mbili juu.

469
00:25:32,598 --> 00:25:35,502
Lakini chini chini, wakati
kufanya kurudi Double Double,

470
00:25:35,502 --> 00:25:38,280
hiyo ni tayari moja kwa moja
kurudi mara mbili muundo.

471
00:25:38,280 --> 00:25:42,278
Kwa nini bado wanahitaji kufafanua
na mshale juu na mara mbili?

472
00:25:42,278 --> 00:25:45,010
>> DAN AMRMENDARIZ: Kwa hiyo
katika kesi, hii ni sehemu

473
00:25:45,010 --> 00:25:50,580
ya the-- hivyo kurudia swali,
kwa sababu ni thabiti kutoka kurudi

474
00:25:50,580 --> 00:25:56,030
aina hapa, ni aina gani hii kwa kweli
ni, tunahitaji kuwa wazi kwa Swift

475
00:25:56,030 --> 00:25:59,970
kuhusu nini tunataka
kurudi nje ya kazi hii

476
00:25:59,970 --> 00:26:02,690
hivyo kwamba wakati hufanya aina
kuangalia, inaweza kuhakikisha

477
00:26:02,690 --> 00:26:05,850
kwamba kile sisi kuwa kweli imeandikwa
chini chini kwa kweli inajilainisha na kwamba.

478
00:26:05,850 --> 00:26:10,225
Hivyo ni aina ya kama kuangalia
na wewe mwenyewe aina ya hali hiyo.

479
00:26:10,225 --> 00:26:11,050
Lakini kuna are--

480
00:26:11,050 --> 00:26:12,560
>> Watazamaji: [inaudible] mshale?

481
00:26:12,560 --> 00:26:19,490
>> DAN AMRMENDARIZ: Kuna matukio wakati
tunaweza bayana kwamba tunaweza inamuunga

482
00:26:19,490 --> 00:26:21,550
kuweka aina ya kurudi.

483
00:26:21,550 --> 00:26:23,940
Lakini katika kesi hii, sijui
kufikiri kwamba ingekuwa kazi.

484
00:26:23,940 --> 00:26:26,190
Kuna baadhi ya syntax mengine
kwamba tutaweza kuona baadaye.

485
00:26:26,190 --> 00:26:30,320

486
00:26:30,320 --> 00:26:35,280
>> Haki wote, hivyo chanzo hiki
kificho ni tofauti kidogo

487
00:26:35,280 --> 00:26:41,839
kwa sababu hii parses hoja kutoka
kazi ambayo sisi ni wito.

488
00:26:41,839 --> 00:26:44,130
Napenda kuonyesha jinsi kazi
kabla ya sisi kweli hoja juu ya

489
00:26:44,130 --> 00:26:48,050
kwa baadhi ya mambo ya kuvutia
yale yanayotokea katika Swift.

490
00:26:48,050 --> 00:26:51,870
>> Hivyo katika kesi hii, kama mimi tu kukimbia hii
kanuni, taarifa kwamba nini anafanya

491
00:26:51,870 --> 00:26:54,900
is-- wakati, ni aina ya
anitiaye makosa weird.

492
00:26:54,900 --> 00:26:59,730
Mimi haja ya kupita michache ya
integers kama hoja mstari amri.

493
00:26:59,730 --> 00:27:06,220
Basi hebu angalia, 150 na 80, na hit Enter
ili kujua nini ni kweli kufanya.

494
00:27:06,220 --> 00:27:09,890
Ni kukubali kila mmoja
maadili haya kama integers.

495
00:27:09,890 --> 00:27:12,040
Ni inputting yao katika gradebook.

496
00:27:12,040 --> 00:27:14,470
Na kisha ni kufanya
kwamba hesabu ya wastani

497
00:27:14,470 --> 00:27:16,650
na outputting kwamba kama sisi bila kutarajia.

498
00:27:16,650 --> 00:27:19,950
>> Lakini ni wazi kuna kitu kinachoendelea
tarehe na hii kumkataa kitu

499
00:27:19,950 --> 00:27:23,300
kitu kama integer.

500
00:27:23,300 --> 00:27:27,300
Kama unaweza kukumbuka kutoka tulipokuwa
kushughulika na hoja mstari amri

501
00:27:27,300 --> 00:27:32,640
katika C na lugha nyingine, kwanza kabisa
0-th bidhaa katika mstari amri hoja kwamba

502
00:27:32,640 --> 00:27:35,774
orodha ni jina la amri
kwamba sisi kweli kunyongwa.

503
00:27:35,774 --> 00:27:38,690
Hivyo katika kesi hii, mimi nina wanaoendesha tu
juu ya yote hoja mstari amri.

504
00:27:38,690 --> 00:27:41,650
Lakini Mimi si kufanya aina yoyote ya dhana
kuangalia ruka juu kwamba moja ya kwanza.

505
00:27:41,650 --> 00:27:45,920
Mimi tu wazi au mimi nina implicitly
kuangalia ambayo ya aina hii

506
00:27:45,920 --> 00:27:49,900
ni integers kabla mimi kwa kweli
kufanya hesabu hii.

507
00:27:49,900 --> 00:27:52,420
>> Na hiyo ndiyo kimsingi
nini kinatokea hapa.

508
00:27:52,420 --> 00:27:55,860
Kwa kila hoja katika
hoja mchakato wa,

509
00:27:55,860 --> 00:27:59,210
Mimi nina kwenda kufanya baadhi ya hundi.

510
00:27:59,210 --> 00:28:01,970
Na katika kesi hii, mimi nina kwenda
kujaribu kubadilisha kwanza

511
00:28:01,970 --> 00:28:07,620
kwamba hoja ndani ya integer na
kufanya typecast wazi,

512
00:28:07,620 --> 00:28:12,310
kwa sababu ni, juu ya pembejeo, kamba
na si kwa kweli integer.

513
00:28:12,310 --> 00:28:18,140
>> Lakini hii ni aina ya syntax weird,
kama basi daraja ni sawa na Int (hoja).

514
00:28:18,140 --> 00:28:21,120
Nini ni kweli yanatokea
hapa ni kubwa mno

515
00:28:21,120 --> 00:28:24,390
muhimu kwa yako kwa kutumia Swift.

516
00:28:24,390 --> 00:28:27,610
Hii ni kwa kutumia nini
aitwaye aina ya hiari.

517
00:28:27,610 --> 00:28:34,790
>> Hivyo kazi hii, Int (hoja),
anarudi si tu integer, lakini anarudi

518
00:28:34,790 --> 00:28:37,470
kile kinachoitwa integer hiari.

519
00:28:37,470 --> 00:28:41,200
Na hivyo hii ni aina ya
Aina juu ya aina.

520
00:28:41,200 --> 00:28:45,900
Unaweza aina ya kufikiria kuwa kama
ni kurudi kama mfuko.

521
00:28:45,900 --> 00:28:47,750
Na wakati wa kufungua kwamba
mfuko, ni ama

522
00:28:47,750 --> 00:28:53,930
ina integer, ambayo ni matokeo, au
ina kitu kabisa ndani yake wakati wote.

523
00:28:53,930 --> 00:28:58,140
Na hii ni muhimu kama kuangalia makosa
utaratibu, kwa sababu katika kesi hii

524
00:28:58,140 --> 00:29:02,080
tunaweza kujua, ilikuwa hii
Aina ya kubadilika na mafanikio?

525
00:29:02,080 --> 00:29:05,810
Kama ilivyokuwa, basi ni kwa kweli
kwenda na integer ndani.

526
00:29:05,810 --> 00:29:08,750
Vinginevyo ni kwenda kuwa na baadhi ya
thamani kwamba tutaweza wito haina kabisa, ambayo

527
00:29:08,750 --> 00:29:10,920
ni mwakilishi wa hakuna integer wakati wote.

528
00:29:10,920 --> 00:29:13,270
Ni kweli mwakilishi wa chochote.

529
00:29:13,270 --> 00:29:18,130
>> Na hivyo hii kama ujenzi
inaruhusu sisi unwrap mfuko huo,

530
00:29:18,130 --> 00:29:19,850
kwamba hiari kisheria.

531
00:29:19,850 --> 00:29:25,560
Na kama sisi ni uwezo wa unwrap kwamba
kufunga na kupata integer ndani,

532
00:29:25,560 --> 00:29:27,720
basi nini tunasema
hapa ni kwamba sisi kisha

533
00:29:27,720 --> 00:29:33,090
kuruhusu thamani kwamba kuwekwa katika
mara kwa mara hii inaitwa daraja.

534
00:29:33,090 --> 00:29:36,590
Na sehemu hii ya kama kauli,
sehemu ya juu ya kauli kama

535
00:29:36,590 --> 00:29:40,390
inakwenda, kwa sababu hiyo
--zingua ilikuwa na mafanikio.

536
00:29:40,390 --> 00:29:43,290
>> Kama ni hivyo tu hutokea kwamba
kulikuwa na makosa labda

537
00:29:43,290 --> 00:29:47,040
katika hii wazi aina kubadilika
kutoka kamba kwa integer, labda

538
00:29:47,040 --> 00:29:49,160
ni thamani ABC kwa mfano.

539
00:29:49,160 --> 00:29:52,120
Na hiyo ni kweli si kwenda
kubadilisha na integer.

540
00:29:52,120 --> 00:29:55,520
Basi itakuwa kurudi haina kabisa,
ambayo si integer.

541
00:29:55,520 --> 00:29:57,570
Na hii ikiwa kauli vizuri kisha kushindwa.

542
00:29:57,570 --> 00:30:01,930
daraja haipo kwa sababu
hana yaliyomo integer.

543
00:30:01,930 --> 00:30:06,391
Na itakuwa kukimbia kuzuia hii kingine badala yake.

544
00:30:06,391 --> 00:30:06,890
Ndiyo?

545
00:30:06,890 --> 00:30:09,652
>> Watazamaji: Nil ni N-I-L?

546
00:30:09,652 --> 00:30:11,110
DAN AMRMENDARIZ: nil ni N-I-L, ndiyo.

547
00:30:11,110 --> 00:30:14,970

548
00:30:14,970 --> 00:30:20,310
>> Hivyo hii ni labda moja ya
mambo ya gumu kuhusu Swift,

549
00:30:20,310 --> 00:30:23,690
hasa wakati uko katika
Magugu juu ya programu iOS

550
00:30:23,690 --> 00:30:27,442
na wewe ni kweli kujaribu
kufanya baadhi ya maendeleo huko.

551
00:30:27,442 --> 00:30:29,400
Ni kwenda kuwa kunguruma
saa wewe kuhusu hiari.

552
00:30:29,400 --> 00:30:33,050
Ni kwenda kuwa na kuuliza wewe kwa
alama ya kuuliza na pointi Moderators.

553
00:30:33,050 --> 00:30:37,100
Lakini mara moja kufikiri out-- kama wewe
kujitolea muda wa kuhesabia

554
00:30:37,100 --> 00:30:41,990
kinachoendelea na aina ya hiari,
wewe utakuwa kujiokoa mengi ya maumivu ya kichwa

555
00:30:41,990 --> 00:30:46,040
kama wewe ni kujaribu
kuandika programu katika Swift.

556
00:30:46,040 --> 00:30:47,660
>> Ni kweli kipengele nguvu sana.

557
00:30:47,660 --> 00:30:49,826
Na wewe utakuwa tu na
kuchukua neno langu kwa ajili yake kwa sasa.

558
00:30:49,826 --> 00:30:52,620
Lakini tutaona ujenzi huu
na baadhi ya watu wengine kama hayo

559
00:30:52,620 --> 00:30:56,740
katika baadhi ya wengine chanzo kanuni kwamba
tutaweza kuonyesha katika kidogo tu.

560
00:30:56,740 --> 00:31:00,440
>> Je, kuna maswali ya awali hapa?

561
00:31:00,440 --> 00:31:03,790

562
00:31:03,790 --> 00:31:08,690
Hivyo takeaway muhimu ni kwamba
hiari aina ni aina ya metatype.

563
00:31:08,690 --> 00:31:12,500
Ni ama ina thamani,
na kama itakuwa hivyo, basi ni

564
00:31:12,500 --> 00:31:18,110
labda na kwamba thamani ya kuhusishwa
pamoja na hayo, au hana thamani yoyote ile,

565
00:31:18,110 --> 00:31:19,620
na ni kuwakilishwa na haina.

566
00:31:19,620 --> 00:31:24,210

567
00:31:24,210 --> 00:31:28,870
Wengine wa hii ni labda
kama ungependa kutarajia.

568
00:31:28,870 --> 00:31:32,900
>> Basi hebu njia panda juu
ugumu bado tena.

569
00:31:32,900 --> 00:31:37,070
Na wakati huu, hebu tuangalie baadhi
aina nyingine takwimu ambazo kweli zipo.

570
00:31:37,070 --> 00:31:41,290
Mmoja wao ni Mkwawa, ambayo ni
sawa na chatu Mkwawa.

571
00:31:41,290 --> 00:31:48,270
Ni kiasi fulani sawa na hash meza katika
C. Ni kimsingi ramani ya funguo

572
00:31:48,270 --> 00:31:49,820
ambapo funguo inaweza kuwa masharti.

573
00:31:49,820 --> 00:31:52,670
Na wakati wewe kuangalia juu funguo hizo,
funguo hizo itakuwa na thamani.

574
00:31:52,670 --> 00:31:56,020
Hivyo si kabisa safu, lakini
badala yake, karibu zaidi zinazohusiana

575
00:31:56,020 --> 00:31:58,810
kwa hash ramani au meza hash.

576
00:31:58,810 --> 00:32:02,420
>> Hebu angalia jinsi hii zinatakiwa
kufanya kazi kabla ya sisi kweli

577
00:32:02,420 --> 00:32:05,210
kwenda katika chanzo kanuni yenyewe.

578
00:32:05,210 --> 00:32:07,680
Kama mimi tu kukimbia hii,
kitu kweli hutokea.

579
00:32:07,680 --> 00:32:12,430
Ni kuwaambia mimi kwamba mimi nina wanatarajia
baadhi ya vigezo vya aina zifuatazo.

580
00:32:12,430 --> 00:32:16,050
Hivyo nina kwenda kutoa kwa
ni baadhi ya majina tatizo kuweka,

581
00:32:16,050 --> 00:32:18,490
hivyo pset0, labda mimi got 100.

582
00:32:18,490 --> 00:32:20,790
Na pset1, I got 5.

583
00:32:20,790 --> 00:32:24,630
Na kisha katika mtihani, mimi
alifanya vizuri na got 30.

584
00:32:24,630 --> 00:32:27,180
Na oops, mimi hit nafasi hapa.

585
00:32:27,180 --> 00:32:30,940
>> Wakati mimi hit Enter, unaweza kuona
hufanya baadhi hesabu.

586
00:32:30,940 --> 00:32:33,740
Inasema gradebook ni tatu
darasa, pset1, pset0, mtihani.

587
00:32:33,740 --> 00:32:36,120
Na gradebook ina
wastani huu maalum.

588
00:32:36,120 --> 00:32:38,370
Hivyo tena, sisi ni kazi
na hii ni wazo gradebook,

589
00:32:38,370 --> 00:32:44,650
lakini sisi ni kwenda kuendelea iterating
na utata wa kazi yetu.

590
00:32:44,650 --> 00:32:47,650
>> Hivyo wakati wa mwanzo, tuko tu
kwenda kujenga kazi ambayo

591
00:32:47,650 --> 00:32:49,390
ina jukumu la kuchapa matumizi.

592
00:32:49,390 --> 00:32:51,920
Na kuna njia ya kutoka hii
kazi ambayo itakuwa tu

593
00:32:51,920 --> 00:32:53,710
kwa nguvu kujiondoa maombi.

594
00:32:53,710 --> 00:32:56,530
Hii si kitu ambacho
utatumia katika iOS programu.

595
00:32:56,530 --> 00:32:59,750
Hii ni tu, katika kesi hii,
na hoja mstari amri.

596
00:32:59,750 --> 00:33:01,990
Ijayo tutaweza kuanza kuelekea kwenye Xcode.

597
00:33:01,990 --> 00:33:07,760
Lakini hii ni maalum kwa amri
mstari style A mpango Swift.

598
00:33:07,760 --> 00:33:11,490
>> Hebu tuangalie baadhi ya
mambo ya kuvutia hapa.

599
00:33:11,490 --> 00:33:15,150
Hebu angalia, michache tu ya
mambo ya kuvutia kutaja labda

600
00:33:15,150 --> 00:33:19,930
ni kwamba katika kazi yangu ya
uchapishaji idadi ya wanafunzi wa darasa,

601
00:33:19,930 --> 00:33:26,090
unaweza kukumbuka kuwa nilikuwa orodha hiyo
ya items-- pset1, pset0, na mtihani.

602
00:33:26,090 --> 00:33:29,130
Unaweza kweli haraka
na kwa urahisi kufanya hivyo

603
00:33:29,130 --> 00:33:34,490
kwa kuchukua gradebook, ambayo ni
kamusi ambayo ina funguo na maadili.

604
00:33:34,490 --> 00:33:38,730
Kupata yote ya msingi ni kupitia
dot funguo njia hapa,

605
00:33:38,730 --> 00:33:43,180
na kisha kutumia joinWithSeparator hii,
ambayo hatimaye kuchukua yote ya funguo

606
00:33:43,180 --> 00:33:48,590
kuwa tulikuwa typed katika, pset1-- au
pole, pset0, pset1, na exam--

607
00:33:48,590 --> 00:33:53,030
na concatenate yao pamoja
kutumia comma na nafasi

608
00:33:53,030 --> 00:33:55,400
kujenga moja kwa muda mrefu kamba.

609
00:33:55,400 --> 00:34:00,190
Hii kujiunga operesheni ni phenomenally
muhimu katika aina mbalimbali za mazingira.

610
00:34:00,190 --> 00:34:03,450
Na hivyo ni joinWithSeparator hii.

611
00:34:03,450 --> 00:34:06,939
>> Na hili ni jambo moja kwamba ni
iliyopita kutoka Swift 1 kwa Swift 2.

612
00:34:06,939 --> 00:34:08,730
Kuna kutumika kwa kuwa
Chatu style-- kama wewe ni

613
00:34:08,730 --> 00:34:13,219
ukoo na Python-- chatu
style kujiunga njia juu ya masharti.

614
00:34:13,219 --> 00:34:15,699
Lakini hiyo ni tena
kesi katika Swift 2.

615
00:34:15,699 --> 00:34:19,400
Unataka kutumia hii kama unataka
kwa concatenate safu ya mambo

616
00:34:19,400 --> 00:34:23,380
pamoja na kamba.

617
00:34:23,380 --> 00:34:27,889
>> Hivyo labda kisha katika yetu
mjadala wa wastani kabla,

618
00:34:27,889 --> 00:34:32,659
inafanya hisia kidogo zaidi
kwa sisi kuweka kazi wastani

619
00:34:32,659 --> 00:34:36,610
kuwa hiari mara mbili badala
kuliko tu mara mbili wazi.

620
00:34:36,610 --> 00:34:39,239
Kwa sababu tulikuwa na kwamba
hali ya kawaida ambapo,

621
00:34:39,239 --> 00:34:41,550
nini kama kweli gradebook
hana maadili ndani yake?

622
00:34:41,550 --> 00:34:44,280
Lazima kurudi wastani nini?

623
00:34:44,280 --> 00:34:46,350
>> Vizuri labda katika C wewe
ingekuwa amefanya kitu

624
00:34:46,350 --> 00:34:50,040
kama zinazotolewa thamani mwangalizi, kama
0.0, au labda idadi hasi,

625
00:34:50,040 --> 00:34:53,690
au kitu tu anayewakilisha ukweli
kuwa kulikuwa na baadhi ya hali makosa

626
00:34:53,690 --> 00:34:57,910
na wewe labda si kweli kuwa
uwezo wa compute kwamba wastani.

627
00:34:57,910 --> 00:35:05,590
Naam uzuri wa kubainisha
hiari aina itakuwa kufanya hivyo.

628
00:35:05,590 --> 00:35:09,540
Na mimi nina sasa akisema maneno hayo yote, lakini
hii kwa kweli haina matumizi optionals.

629
00:35:09,540 --> 00:35:12,970
Lakini tutaweza kuona kwamba katika tu
Dakika ambapo tunaweza kuweka wastani

630
00:35:12,970 --> 00:35:17,230
kuwa data hiari aina ili
kama kweli anarudi baadhi ya data, kisha

631
00:35:17,230 --> 00:35:18,470
tutarudi data hizo.

632
00:35:18,470 --> 00:35:20,570
Vinginevyo sisi kurudi
haina kabisa, akisema kuwa hii

633
00:35:20,570 --> 00:35:22,200
hana hesabu ya maana.

634
00:35:22,200 --> 00:35:25,650

635
00:35:25,650 --> 00:35:28,570
>> Hebu hoja juu ya kitu kingine.

636
00:35:28,570 --> 00:35:35,910
Hivyo kutoka hapa, tumekuwa kuangalia
mifano yote haya katika mstari amri.

637
00:35:35,910 --> 00:35:39,470
Lakini kwa kweli nini wewe kwenda
kuwa kushughulika na ni Xcode.

638
00:35:39,470 --> 00:35:43,720
Na moja ya mambo mazuri kuhusu
Xcode ni, na hasa katika Swift,

639
00:35:43,720 --> 00:35:47,450
ni kwamba tuna hii
Jambo aitwaye Uwanja wa michezo.

640
00:35:47,450 --> 00:35:51,470
Na Uwanja wa michezo ni
si wakati programu zote iOS.

641
00:35:51,470 --> 00:35:54,751
Lakini utapata majaribio
pamoja Swift kwa njia rahisi sana.

642
00:35:54,751 --> 00:35:56,000
Unaweza aina zote za kanuni yako.

643
00:35:56,000 --> 00:35:58,140
Ni vizuri syntax yalionyesha hapa.

644
00:35:58,140 --> 00:36:01,600
Wakati kujenga faili mpya, kuuliza
wewe kama unataka kujenga Uwanja wa michezo.

645
00:36:01,600 --> 00:36:08,720
Lakini jambo zuri kuhusu Uwanja wa michezo
ni kwamba juu ya haki ya dirisha yako,

646
00:36:08,720 --> 00:36:12,020
je, ni kweli kuonyesha
pato kutoka kanuni yako.

647
00:36:12,020 --> 00:36:16,110
Hivyo kama mimi kitabu chini, tunaweza kuona nini
pato la mistari mbalimbali ya maadili

648
00:36:16,110 --> 00:36:17,200
kweli hutokea kwa kuwa.

649
00:36:17,200 --> 00:36:19,850

650
00:36:19,850 --> 00:36:26,790
>> Hivyo katika kesi hii, tunakwenda
mabadiliko maelekezo kidogo tu

651
00:36:26,790 --> 00:36:30,960
na majadiliano juu ya kitu ambacho ni kweli
muhimu kwa kiwango hiki njia ya juu

652
00:36:30,960 --> 00:36:34,020
kwamba Swift kazi, na
ni wazo hili la kufungwa.

653
00:36:34,020 --> 00:36:36,960
Na ve pengine kuona hii
kidogo katika JavaScript.

654
00:36:36,960 --> 00:36:40,770
Kwa wale kwamba
ni katika CS50, kufungwa

655
00:36:40,770 --> 00:36:47,240
ni maarufu sana, njia nzuri sana ya kufanya
kiwango cha juu ya mambo katika lugha ya kisasa.

656
00:36:47,240 --> 00:36:50,270
Lakini pia ni aina ya vigumu
wrap kichwa yako karibu mara ya kwanza.

657
00:36:50,270 --> 00:36:52,269
Hivyo kama wewe kuangalia hii
mara ya kwanza, hiyo ni sawa.

658
00:36:52,269 --> 00:36:56,740
Tu kuangalia chanzo kanuni na kuona
kama unaweza takwimu ni nje ya nyumbani.

659
00:36:56,740 --> 00:37:01,050
>> Hivyo katika kesi hii, hebu kusema kwamba sisi
wanataka kujenga mengi ya mashujaa

660
00:37:01,050 --> 00:37:04,134
pamoja na baadhi ya thamani ya kudumu.

661
00:37:04,134 --> 00:37:05,800
Hivyo katika kesi hii mimi inaweza kujenga kazi.

662
00:37:05,800 --> 00:37:09,270
Mimi nina kwenda kuiita nguvu za
2 ambao lengo pekee katika maisha

663
00:37:09,270 --> 00:37:15,770
ni kuchukua baadhi ya pembejeo na mara mbili
yake, na kurudi thamani hiyo.

664
00:37:15,770 --> 00:37:21,210
Taarifa kwamba mimi hapa
kukubali aina moja ya data.

665
00:37:21,210 --> 00:37:23,137
Ni kwenda kuwa variable kuitwa x.

666
00:37:23,137 --> 00:37:23,970
Ni ya aina Double.

667
00:37:23,970 --> 00:37:26,190
Na mimi nina kwenda na kurudi mara mbili hapa.

668
00:37:26,190 --> 00:37:29,100
Na mimi nina kwenda tu kufanya
sana, kusema ukweli, pretty

669
00:37:29,100 --> 00:37:32,650
njia wasiojua wa mara dufu thamani huu.

670
00:37:32,650 --> 00:37:35,600
Na mimi nitakuonyesha nini hii
ni muhimu katika haki ya pili.

671
00:37:35,600 --> 00:37:40,418
>> Taarifa kwamba hapa tuna mbalimbali huu
tena. kwa ajili ya kitu katika 1, nukta

672
00:37:40,418 --> 00:37:44,130
dot dot, 2, ambayo ina maana kwamba
kitanzi hii inakwenda mara mbili.

673
00:37:44,130 --> 00:37:46,480
Lakini hii inawakilisha kutofautiana dummy.

674
00:37:46,480 --> 00:37:49,650
Ina maana mimi si kweli kwenda
kutumia kwamba kutofautiana popote

675
00:37:49,650 --> 00:37:51,070
ndani ya kitanzi hii.

676
00:37:51,070 --> 00:37:55,380
Mimi nataka tu mstari huu
ya maadili ya kuendesha mara mbili,

677
00:37:55,380 --> 00:37:58,980
bila wanaohitaji kujua
thamani ya mbalimbali.

678
00:37:58,980 --> 00:38:02,570
>> Hivyo katika kesi hii mimi nina mbio matokeo
mara x mara mbili, ambayo kimsingi

679
00:38:02,570 --> 00:38:06,560
ina maana kwamba mimi nina squaring thamani huu.

680
00:38:06,560 --> 00:38:10,230
Na hii hufanyika kwa
kazi kama sisi bila kutarajia.

681
00:38:10,230 --> 00:38:16,410
Nguvu ya 2, kupita thamani ya
2.0 inatupa pato la 4.

682
00:38:16,410 --> 00:38:18,810
3.2 Kazi kwa 10.24.

683
00:38:18,810 --> 00:38:22,660
>> Sasa tunaweza kufanya sawa
Jambo kwa nguvu ya 3.

684
00:38:22,660 --> 00:38:25,330
Lakini sasa kubadili tu mbalimbali.

685
00:38:25,330 --> 00:38:28,840
Kwa dummy kutofautiana katika 1
kupitia 3, kuzidisha mara 3,

686
00:38:28,840 --> 00:38:29,830
na kufanya kitu kimoja.

687
00:38:29,830 --> 00:38:32,240
>> Hivyo hii inaweza kujisikia kidogo contrived.

688
00:38:32,240 --> 00:38:34,270
Lakini kuna muhimu
Jambo hapa ambayo

689
00:38:34,270 --> 00:38:37,770
ni kwamba kuangalia hizi
kazi mbili, kuna

690
00:38:37,770 --> 00:38:43,600
jambo moja tu kwamba ni tofauti,
ambayo ni thamani hii katika mbalimbali.

691
00:38:43,600 --> 00:38:46,910
Kila kitu kingine kuhusu hizi mbili
kazi, uwezo wa 3 na uwezo wa 2,

692
00:38:46,910 --> 00:38:50,440
ni, kwa kweli, kufanana kwa sababu
wanafanya kazi katika njia hiyo hiyo.

693
00:38:50,440 --> 00:38:53,460
>> Hivyo katika hatua hii, kidogo
kengele kengele inapaswa kwenda mbali.

694
00:38:53,460 --> 00:38:56,200
Hopefully unachosema,
unajua, hii anahisi kidogo

695
00:38:56,200 --> 00:38:59,250
kama kurudia ya juhudi.

696
00:38:59,250 --> 00:39:02,950
Labda kuna njia ni kwamba napenda
kuwa na uwezo wa kurejelea haya yote

697
00:39:02,950 --> 00:39:06,630
na kutoa kazi
au kuunda kazi ambayo

698
00:39:06,630 --> 00:39:11,550
gani hasa nini nataka bila
wanaohitaji aina yake nje waziwazi.

699
00:39:11,550 --> 00:39:15,732
Na hii ni nini nguvu
ya kufungwa inaruhusu sisi kufanya.

700
00:39:15,732 --> 00:39:16,940
Basi hebu tuangalie hii.

701
00:39:16,940 --> 00:39:18,700
Na mimi itabidi kutumia michache
Dakika juu ya hili, kwa sababu hii

702
00:39:18,700 --> 00:39:20,310
ni pretty muhimu kwa Swift.

703
00:39:20,310 --> 00:39:22,900
Tunaona hii wakati wote.

704
00:39:22,900 --> 00:39:24,550
Tunakwenda kufafanua kazi.

705
00:39:24,550 --> 00:39:26,380
Ni kwenda kuitwa powerOf.

706
00:39:26,380 --> 00:39:29,470
Ni kwenda kukubali
parameter aitwaye y ya aina Int.

707
00:39:29,470 --> 00:39:32,220
Lakini tuangalie aina ya kurudi.

708
00:39:32,220 --> 00:39:38,730
Aina ya kurudi ni, katika
mabano, Double Double mshale.

709
00:39:38,730 --> 00:39:43,370
Ambayo ina maana kwamba kazi hii,
hii powerOf kazi,

710
00:39:43,370 --> 00:39:46,550
ni kurudi kazi.

711
00:39:46,550 --> 00:39:50,845
Hiyo ni kukubali Double
na kurudi mara mbili.

712
00:39:50,845 --> 00:39:53,720
Hivyo kwamba ili sauti aina ya mambo,
lakini hebu kitabu chini kidogo

713
00:39:53,720 --> 00:39:55,060
na kuangalia na kuona nini kinatokea.

714
00:39:55,060 --> 00:39:57,910
Tuko ndani ya hii powerOf kazi.

715
00:39:57,910 --> 00:40:00,760
Sisi ni kujenga kazi mpya
aitwaye exponentiator,

716
00:40:00,760 --> 00:40:02,900
lakini haijalishi ni nini.

717
00:40:02,900 --> 00:40:06,410
>> Taarifa kwamba hii ina
pembejeo thamani ya x.

718
00:40:06,410 --> 00:40:09,910
Na ni kuchukua katika mara mbili
na kurudi mara mbili.

719
00:40:09,910 --> 00:40:16,320
Na hii ni kanuni sawa kwamba sisi
ona hapo juu, ila kwa kuwa thamani ya 2

720
00:40:16,320 --> 00:40:20,060
au thamani ya 3, kwamba
juu amefungwa katika mbalimbali,

721
00:40:20,060 --> 00:40:23,210
imekuwa kubadilishwa na
thamani huu wa y, ambayo

722
00:40:23,210 --> 00:40:27,230
ilikuwa parameter ya awali
ya powerOf yetu kufanya kazi.

723
00:40:27,230 --> 00:40:31,700
Na katika hatua hii, sisi
kurudi exponentiator.

724
00:40:31,700 --> 00:40:33,345
Tuko kurudi kazi.

725
00:40:33,345 --> 00:40:36,300

726
00:40:36,300 --> 00:40:39,550
>> Ni aina ya kama kidogo akili unavuma.

727
00:40:39,550 --> 00:40:44,360
Lakini hebu fikiria nini kinatokea
wakati mimi kuwaita kazi hii powerOf

728
00:40:44,360 --> 00:40:47,610
na kupita ndani yake baadhi thamani kama 2.

729
00:40:47,610 --> 00:40:50,020
Hii ina maana kwamba
Mimi sasa kuwa na thamani

730
00:40:50,020 --> 00:40:55,130
2 kwa y, ambayo ina maana kwamba thamani hii
y katika hii kazi exponentiator

731
00:40:55,130 --> 00:40:56,410
itakuwa kwamba thamani 2.

732
00:40:56,410 --> 00:41:01,290
Lakini mimi nina kurudi huu
exponentiator kazi.

733
00:41:01,290 --> 00:41:05,900
>> Hivyo taarifa gani Swift anasema mimi
tumemuumba katika kesi hii.

734
00:41:05,900 --> 00:41:10,550
basi mraba ni ufafanuzi, ni
kazi ambayo anapokea Double

735
00:41:10,550 --> 00:41:12,610
na anarudi Double.

736
00:41:12,610 --> 00:41:16,590
I have umba kazi
kwamba viwanja kitu

737
00:41:16,590 --> 00:41:19,782
kutumia utaratibu huu hapa hapa.

738
00:41:19,782 --> 00:41:22,490
Na kwa kweli nini kinatokea ni
kuwa ni kurudi kazi hii

739
00:41:22,490 --> 00:41:26,390
exponentiator, lakini thamani huu
y umefungwa ndani yake.

740
00:41:26,390 --> 00:41:31,080
Na hivyo sasa kila wakati mimi kutumia hii
kutofautiana au mara kwa mara hii inaitwa

741
00:41:31,080 --> 00:41:35,180
mraba, ni itakuja
kuwa na tabia kama kazi.

742
00:41:35,180 --> 00:41:39,960
Na hivyo siwezi kisha kuwaita kwamba kutofautiana
kama napenda kuwaita kazi,

743
00:41:39,960 --> 00:41:43,830
na kupita ndani yake idadi,
kama katika kesi hii 3.

744
00:41:43,830 --> 00:41:45,910
Nami kisha mraba thamani huu.

745
00:41:45,910 --> 00:41:53,340
Hivyo 3 mraba kisha
kuwa 9, kama tunaweza kuona hapa.

746
00:41:53,340 --> 00:41:56,530
>> Kweli mambo, lakini hii sasa
inaruhusu mimi nafasi

747
00:41:56,530 --> 00:41:59,040
kujenga kazi nyingine powerOf.

748
00:41:59,040 --> 00:42:03,680
Kama naweza kusema, OK, vizuri sasa nataka
kujenga kazi mpya, powerOf (3),

749
00:42:03,680 --> 00:42:06,290
na kuhifadhi kwamba katika
mara kwa mara aitwaye mchemraba.

750
00:42:06,290 --> 00:42:10,220
Na sasa mchemraba ni kwenda kuwa
kazi tofauti kwamba mapenzi kisha

751
00:42:10,220 --> 00:42:14,800
kuchukua baadhi ya thamani kama pembejeo na mchemraba kwamba
thamani kama tunaweza kuona katika mstari wa chini

752
00:42:14,800 --> 00:42:16,420
hapa.

753
00:42:16,420 --> 00:42:18,590
mchemraba wa 2 ni kwenda kusababisha 8.

754
00:42:18,590 --> 00:42:21,330

755
00:42:21,330 --> 00:42:22,680
>> Hopefully pretty nadhifu mambo ya ajabu.

756
00:42:22,680 --> 00:42:25,920
Wewe sijawahi kuona hili kabla.

757
00:42:25,920 --> 00:42:29,990
Mimi moyo kuangalia ndani kufungwa
na kuchunguza hii kidogo zaidi.

758
00:42:29,990 --> 00:42:33,570
Ni mambo ya ajabu kweli nguvu tunaona mengi
katika JavaScript na baadhi lugha nyingine.

759
00:42:33,570 --> 00:42:37,160
Ni kweli muhimu kwa
kuelewa APIs pamoja

760
00:42:37,160 --> 00:42:38,620
kwamba tutaweza kupata katika haki ya pili.

761
00:42:38,620 --> 00:42:39,456
Ndiyo?

762
00:42:39,456 --> 00:42:43,740
>> Watazamaji: Wakati wa kufanya
powerOf (2), mabano, na kisha

763
00:42:43,740 --> 00:42:48,764
mabano nyingine, input-- nyingine
wewe ni kimsingi kuondoa mraba.

764
00:42:48,764 --> 00:42:50,930
DAN AMRMENDARIZ: Ili kuangalia
katika mstari wa mwisho kabisa hapa.

765
00:42:50,930 --> 00:42:55,930
Ni kweli kabisa inawezekana
kufanya hivyo chaining kama wewe unahitajika.

766
00:42:55,930 --> 00:43:00,990
Hivyo powerOf (5) ina maana kwamba tunakwenda
kuwa na exponentiator ya 5 hapa.

767
00:43:00,990 --> 00:43:04,160
Hivyo hii ni kimsingi kwenda kuwa
kitu kimoja kama 4 madarakani tano,

768
00:43:04,160 --> 00:43:07,200
kwa sababu tumeunda exponentiating
kazi kwa nguvu ya tano,

769
00:43:07,200 --> 00:43:09,920
na sisi ni kupita katika
kwamba kazi thamani 4.

770
00:43:09,920 --> 00:43:12,619
Na sisi kupata thamani kwamba
kwamba sisi kutarajia, 1024.

771
00:43:12,619 --> 00:43:14,785
Watazamaji: Na si
jina, hivyo inafanya kuwa rahisi

772
00:43:14,785 --> 00:43:16,570
kusoma, mraba chochote.

773
00:43:16,570 --> 00:43:17,903
>> DAN AMRMENDARIZ: Haki, hasa.

774
00:43:17,903 --> 00:43:21,120
Hivyo kabla ya mimi tu ya kuweka
ndani ya mara kwa mara hapa ili

775
00:43:21,120 --> 00:43:23,808
kuwa alifanya hivyo rahisi kutumia jina hilo.

776
00:43:23,808 --> 00:43:24,308
Ndiyo?

777
00:43:24,308 --> 00:43:26,942
>> Watazamaji: Katika hali hii
powerOf, ni sehemu

778
00:43:26,942 --> 00:43:30,774
ya lugha ya programu
kinyume na njia

779
00:43:30,774 --> 00:43:33,952
kufikiria powerOf katika [inaudible]?

780
00:43:33,952 --> 00:43:35,660
DAN AMRMENDARIZ: Kwa hiyo
katika kesi hiyo, powerOf

781
00:43:35,660 --> 00:43:39,280
ni tu jina la
kazi ambayo mimi inavyoelezwa hapa.

782
00:43:39,280 --> 00:43:41,801
Hivyo si asili
kwa lugha yenyewe,

783
00:43:41,801 --> 00:43:43,550
lakini badala yake, ni tu
kazi ambayo ina

784
00:43:43,550 --> 00:43:45,628
jina kwamba kwa sababu mimi kuwapa jina hilo.

785
00:43:45,628 --> 00:43:48,770

786
00:43:48,770 --> 00:43:51,920
Yoyote maswali mengine?

787
00:43:51,920 --> 00:43:52,800
Sawa.

788
00:43:52,800 --> 00:43:54,750
>> Sasa hii ni kubwa.

789
00:43:54,750 --> 00:43:58,170
Lakini wewe si kwenda kuona
mengi ya kazi kufungwa kwamba

790
00:43:58,170 --> 00:44:03,440
ni kama hii ambapo unaweza kufafanua, ndani ya
ya kazi moja, kazi nyingine.

791
00:44:03,440 --> 00:44:04,320
Na unaweza kufanya hivyo.

792
00:44:04,320 --> 00:44:06,430
Lakini ni aina ya si
kweli muhimu, sawa?

793
00:44:06,430 --> 00:44:09,189
Kama kwa nini mimi kufafanua hii
kazi kuitwa exponentiator

794
00:44:09,189 --> 00:44:10,480
na kisha mara moja kurudi.

795
00:44:10,480 --> 00:44:15,220
Kwa nini hawawezi mimi tu mara moja
kurudi kazi hii?

796
00:44:15,220 --> 00:44:18,890
>> Na kwa kweli, hii ni just
Dhana ya dhana iitwayo

797
00:44:18,890 --> 00:44:22,410
kazi bila majina, ambapo
kazi bila majina si kweli

798
00:44:22,410 --> 00:44:25,270
na jina kwa sababu wao
huna haja ya kuwa na mtu mmoja.

799
00:44:25,270 --> 00:44:28,700
Na hivyo katika kesi hii, katika 7B,
tunaweza kupata just kwamba.

800
00:44:28,700 --> 00:44:31,470
Ni wote kificho huo,
hasa kitu kimoja gani,

801
00:44:31,470 --> 00:44:35,570
lakini sasa tumekuwa iliyopita ni kidogo hivyo
kwamba hii kazi mara moja powerOf

802
00:44:35,570 --> 00:44:37,750
anarudi kazi.

803
00:44:37,750 --> 00:44:44,150
Taarifa kwamba baada ya kurudi,
kuna wazi curly mabano.

804
00:44:44,150 --> 00:44:46,410
Ni tegemeo pembejeo hii Double.

805
00:44:46,410 --> 00:44:48,560
Ni kutarajia kwamba pato Double.

806
00:44:48,560 --> 00:44:52,175
Na kisha katika neno la
hutenganisha kificho yenyewe.

807
00:44:52,175 --> 00:44:53,550
Hivyo hii ni kazi bila majina.

808
00:44:53,550 --> 00:44:57,030
Haina kweli kuwa jina, ambapo
kabla ilikuwa inaitwa exponentiator.

809
00:44:57,030 --> 00:45:00,229
Lakini kama tuliona, tu kwa kweli
hakuwa rejea exponentiator

810
00:45:00,229 --> 00:45:01,270
nje ya kazi hiyo.

811
00:45:01,270 --> 00:45:02,470
Hivyo hakuwa na jambo hilo.

812
00:45:02,470 --> 00:45:06,300
Hivyo kazi hii bila majina ni
kinachojulikana kwa sababu ni Nameless,

813
00:45:06,300 --> 00:45:09,107
lakini bado inatumiwa
katika mazingira ya kanuni hii.

814
00:45:09,107 --> 00:45:13,690

815
00:45:13,690 --> 00:45:16,079
>> Ijayo wanandoa ndio mimi nina
kwenda kuendelea hopefully

816
00:45:16,079 --> 00:45:17,370
kupiga akili yako kidogo.

817
00:45:17,370 --> 00:45:20,410
Tunaweza kurahisisha hii hata zaidi.

818
00:45:20,410 --> 00:45:24,490
Kwa sababu kama alikuwa astutely
Alisema awali,

819
00:45:24,490 --> 00:45:29,100
labda sisi kweli kujua, na
inferring kutoka kanuni hii, ni nini

820
00:45:29,100 --> 00:45:31,750
pato la kanuni hizi ni kwenda kuwa.

821
00:45:31,750 --> 00:45:38,180
Na kwa kweli, katika kazi hii bila majina,
tunaweza kwa kweli kudai aina ya data.

822
00:45:38,180 --> 00:45:41,650
>> Hivyo katika hili, sisi tena
haja ya kupanga kufafanua

823
00:45:41,650 --> 00:45:44,850
aina ya data hiyo kuwa
pembejeo na mazao kutokana na kazi hii

824
00:45:44,850 --> 00:45:45,890
kwa michache ya sababu.

825
00:45:45,890 --> 00:45:51,390
Moja ni kwamba tumekuwa inavyoelezwa, hadi saa
mfano wa enclosing kazi,

826
00:45:51,390 --> 00:45:55,770
ni aina gani ya data bila majina huu
kazi lazima pembejeo na mazao.

827
00:45:55,770 --> 00:45:57,900
Na kutoka nyingine, sisi
unaweza infer kutoka kificho

828
00:45:57,900 --> 00:46:01,930
chini hapa kwamba sisi ni kukubali
pembejeo kwamba ni wa aina Double

829
00:46:01,930 --> 00:46:03,670
na kurudi mara mbili.

830
00:46:03,670 --> 00:46:07,890
>> Taarifa kwamba hapa tuna si wazi
inavyoelezwa majina ya hoja

831
00:46:07,890 --> 00:46:11,220
kuwa kazi hii ni kukubali.

832
00:46:11,220 --> 00:46:16,180
Na hivyo tunaona tunaweza kutaja
vigezo wale kutumia $ 0, $ 1,

833
00:46:16,180 --> 00:46:20,140
kadhalika na kadhalika, kutegemeana na
idadi ya kwamba parameter kutumika

834
00:46:20,140 --> 00:46:20,850
katika kazi hii.

835
00:46:20,850 --> 00:46:23,370

836
00:46:23,370 --> 00:46:29,740
>> Hili ni jambo ambalo unaenda
kuona mengi ni hili wazi curly mabano

837
00:46:29,740 --> 00:46:32,797
ufafanuzi ikifuatiwa na
$ 0, na kisha baadhi ya operesheni,

838
00:46:32,797 --> 00:46:34,130
na kisha kufungwa curly mabano.

839
00:46:34,130 --> 00:46:38,630
Hiyo ni kazi bila majina
ambayo hufanya operesheni hii.

840
00:46:38,630 --> 00:46:42,940
Ina parameter hii ambapo
ni aina ni inferred.

841
00:46:42,940 --> 00:46:44,860
Hiyo parameter kwanza ni $ 0.

842
00:46:44,860 --> 00:46:49,010
Na baadhi ya operesheni ni
kinatokea kwenye kwamba $ 0.

843
00:46:49,010 --> 00:46:52,100
>> Watazamaji: Hivyo ishara ya dola
ina maana parameter kimsingi,

844
00:46:52,100 --> 00:46:53,429
na 0 maana yake ni moja ya kwanza?

845
00:46:53,429 --> 00:46:54,720
DAN Armendáriz: Hiyo ni sahihi.

846
00:46:54,720 --> 00:46:59,100
Hivyo ishara ya dola kimsingi ina maana
parameter, na 0 ina maana moja kwanza.

847
00:46:59,100 --> 00:47:02,760
Lakini ni kazi hasa katika
kesi hii ambapo mimi si jina lake

848
00:47:02,760 --> 00:47:07,940
hoja katika kazi yangu bila majina.

849
00:47:07,940 --> 00:47:11,119
>> Watazamaji: Je, Perl au kitu na
ishara hii ya dola, dola 0 katika huko?

850
00:47:11,119 --> 00:47:12,702
DAN Armendáriz: Je ambayo, samahani?

851
00:47:12,702 --> 00:47:15,360
Watazamaji: Je Perl na
dola hii 0, dola 1--

852
00:47:15,360 --> 00:47:17,318
DAN Armendáriz: Sina
pia ukoo na Perl,

853
00:47:17,318 --> 00:47:21,340
lakini PHP nini amefafanua vigezo
kulingana na ishara ya dola.

854
00:47:21,340 --> 00:47:26,120
Na kunaweza kuwa na baadhi ya lugha
kwamba kuwa na sifa kama hii.

855
00:47:26,120 --> 00:47:28,240
Kwa kweli, Swift borrows
mengi ya makala kama hii

856
00:47:28,240 --> 00:47:29,489
kutoka mengi ya lugha nyingine.

857
00:47:29,489 --> 00:47:32,380
Tunaona mwanga wa chatu ndani yake.

858
00:47:32,380 --> 00:47:35,800
Ufafanuzi huu wa aina
inaonekana kuja kutoka OCaml.

859
00:47:35,800 --> 00:47:38,932
Na tuna tu rundo zima la
mambo kutoka kura ya lugha mbalimbali.

860
00:47:38,932 --> 00:47:40,640
Hiyo ni moja ya nzuri
mambo kuhusu Swift

861
00:47:40,640 --> 00:47:43,390
ni kwamba inachukua mengi ya bora
mawazo kutoka kundi la lugha

862
00:47:43,390 --> 00:47:47,229
na shoehorns wote pamoja
katika lugha moja super.

863
00:47:47,229 --> 00:47:49,520
Kwa kweli, kama wewe naomba
kuendelea kupiga akili yako,

864
00:47:49,520 --> 00:47:51,000
hivyo tumekuwa kufanya haya yote.

865
00:47:51,000 --> 00:47:56,690
Tunaweza labda kurahisisha hii kidogo
kidogo kwa kutambua kwamba, bila shaka,

866
00:47:56,690 --> 00:48:02,120
Swift ina exponentiating
kazi kujengwa katika.

867
00:48:02,120 --> 00:48:04,660
Kama mimi kuagiza Darwin, ambayo
ni tu maktaba ambayo

868
00:48:04,660 --> 00:48:09,680
makala kazi kuitwa hii pow, sasa
Siwezi kurahisisha uwezo wangu wa kazi

869
00:48:09,680 --> 00:48:11,830
kuwa yafuatayo.

870
00:48:11,830 --> 00:48:15,860
Ni kwenda kuwa kurudi
kazi hii bila majina.

871
00:48:15,860 --> 00:48:17,950
>> Lakini tuangalie jinsi rahisi hii ni sasa.

872
00:48:17,950 --> 00:48:22,780
Hii ni kazi bila majina kwamba
ni kukubali baadhi ya aina ya data,

873
00:48:22,780 --> 00:48:26,600
na ni kwenda kuwa moja
Hoja hasa,

874
00:48:26,600 --> 00:48:29,320
inatazamwa katika $ 0 kwamba ni ya aina Double.

875
00:48:29,320 --> 00:48:32,680
Ni kwenda na kurudi aina Double.

876
00:48:32,680 --> 00:48:35,760
Lakini kauli kurudi
sasa thabiti.

877
00:48:35,760 --> 00:48:39,990
>> Na ni mtindo huu halisi kwamba
ni sana, imefikia sana katika Swift,

878
00:48:39,990 --> 00:48:40,790
kila mahali.

879
00:48:40,790 --> 00:48:43,190
Tunakwenda kuona hii
muda wote katika Swift.

880
00:48:43,190 --> 00:48:46,150
Hivyo mimi nina kuonyesha yote haya kwa
wewe kwa sababu ya syntax hii.

881
00:48:46,150 --> 00:48:49,070
Hii ni kawaida sana
kuona, maana yake

882
00:48:49,070 --> 00:48:51,420
ni kazi bila majina
kwamba ni kufanya

883
00:48:51,420 --> 00:48:54,640
baadhi ya operesheni juu ya hoja hizi.

884
00:48:54,640 --> 00:48:56,940
Na kuna kurudi thabiti.

885
00:48:56,940 --> 00:49:01,850
Hivyo ni kabisa kitu kimoja
kwetu kusema hayo, haki hapa.

886
00:49:01,850 --> 00:49:05,730

887
00:49:05,730 --> 00:49:08,150
>> Kwa sababu curly hii
mabano ni kazi,

888
00:49:08,150 --> 00:49:10,480
tuko kufanya operesheni hii
juu ya hoja ya kwanza.

889
00:49:10,480 --> 00:49:12,170
Sisi ni kwenda na kurudi hivyo.

890
00:49:12,170 --> 00:49:14,815
Lakini kurudi hii nje ni
kurudi kazi ile yote,

891
00:49:14,815 --> 00:49:19,855
kwamba kazi nzima bila majina
kwamba tumekuwa tu kuundwa.

892
00:49:19,855 --> 00:49:21,689
Yoyote maswali mengine?

893
00:49:21,689 --> 00:49:23,980
Sawa, mimi sijui kama
nyie ni tayari kwa ajili ya hii,

894
00:49:23,980 --> 00:49:27,455
lakini tunaweza kwenda hata crazier na Swift.

895
00:49:27,455 --> 00:49:28,560
Uko tayari?

896
00:49:28,560 --> 00:49:29,930
OK, hii ni kubwa.

897
00:49:29,930 --> 00:49:35,310
>> Sasa sisi kweli kuwa na uwezo
kwa, katika Swift, kwa sababu ya jinsi msimu

898
00:49:35,310 --> 00:49:39,650
na jinsi itifaki msingi ni, kwa
kufafanua wetu waendeshaji wenyewe freaking.

899
00:49:39,650 --> 00:49:44,060
Kama katika kesi hii, hatukuwa na
alama kwa exponentiation-- vizuri,

900
00:49:44,060 --> 00:49:47,990
kwa ajili ya kufanya nguvu za kitu.

901
00:49:47,990 --> 00:49:53,632
Lakini siwezi, katika Swift, kufafanua mpya
alama kwamba hana just kwamba.

902
00:49:53,632 --> 00:49:55,590
Hivyo katika kesi hii kuna
rundo la syntax hapa.

903
00:49:55,590 --> 00:49:59,980
Na mimi itabidi kuruhusu kuangalia ni
nyumbani wakati ukiangalia hiyo.

904
00:49:59,980 --> 00:50:06,890
Lakini sisi ni kufafanua infix hii
operator, **, ambayo hatimaye kuruhusu sisi,

905
00:50:06,890 --> 00:50:09,840
na kufafanua kile kwamba
kazi ** kweli

906
00:50:09,840 --> 00:50:15,010
haina, kukubali mkono wa kushoto
upande na upande wa kulia,

907
00:50:15,010 --> 00:50:21,190
na kisha kurudi exponent ya kwamba
mkono wa kushoto upande kwa upande wa kulia.

908
00:50:21,190 --> 00:50:24,850
>> Na hivyo sasa wote wa mimi ghafla
tumemuumba kadiri mpya.

909
00:50:24,850 --> 00:50:29,490
Hivyo 2 ** 3 ina maana 2 madarakani tatu.

910
00:50:29,490 --> 00:50:34,420
[AKILI BLOWING SOUND] Hii na
yenyewe lazima uwe kuwa kama,

911
00:50:34,420 --> 00:50:37,960
OK, parafujo C. mimi nina kwenda
Swift njia yote.

912
00:50:37,960 --> 00:50:38,740
Hii ni kubwa.

913
00:50:38,740 --> 00:50:40,140
Hii ni pretty ajabu.

914
00:50:40,140 --> 00:50:42,240
>> Ingawa hii ni mfano mkubwa.

915
00:50:42,240 --> 00:50:45,570
Lakini nina kamwe mara moja nje
ya mfano huu kwa kweli

916
00:50:45,570 --> 00:50:46,800
inavyoelezwa operator yangu mwenyewe.

917
00:50:46,800 --> 00:50:49,710
Lakini bado, inaonyesha
mengi ya nguvu ya Swift

918
00:50:49,710 --> 00:50:54,050
na kwa nini hii ni kweli
kweli baridi sana.

919
00:50:54,050 --> 00:50:55,832
OK, ndiyo?

920
00:50:55,832 --> 00:50:57,790
Watazamaji: Kama uko
kufafanua operator yako mwenyewe,

921
00:50:57,790 --> 00:51:02,940
jinsi gani unajua huna ajali
kujaribu na kujenga operator hiyo ni

922
00:51:02,940 --> 00:51:06,040
katika mahali fulani katika C, kama
siri mahali fulani katika Swift,

923
00:51:06,040 --> 00:51:12,210
kama moja Obscure kwamba
inaweza kuwa kuona mbele.

924
00:51:12,210 --> 00:51:15,050
>> DAN Armendáriz: Hivyo kama wewe ni kujaribu
kufafanua waendeshaji yako mwenyewe,

925
00:51:15,050 --> 00:51:20,970
kuna hatari ya kufafanua
moja juu ya alama zilizopo.

926
00:51:20,970 --> 00:51:24,870
Kwamba huenda katika ngazi ya kina kwamba
Sidhani kama tuna muda wa kwenda juu.

927
00:51:24,870 --> 00:51:27,620
Lakini hiyo ni hatari.

928
00:51:27,620 --> 00:51:31,320
Na kwamba kwa kweli ni sababu sana kwa nini
Sikuwa kutumia kareti ishara, ambayo

929
00:51:31,320 --> 00:51:36,210
wakati sisi ni kuandika nje nguvu, sisi kwa kawaida
kutumia 4 kidogo kareti 5 au kitu

930
00:51:36,210 --> 00:51:40,560
kama kwamba, tu wakati tuko
Gchatting marafiki au chochote.

931
00:51:40,560 --> 00:51:43,660
Lakini katika kesi hiyo, kwamba kweli
ingekuwa unasababishwa mgongano.

932
00:51:43,660 --> 00:51:46,450
Na hivyo mimi kuepukwa ni kwa sababu tu
Mimi kilichotokea kwa kujua katika kesi hiyo

933
00:51:46,450 --> 00:51:50,430
kwamba ambayo ingeweza kusababisha kwamba mgongano.

934
00:51:50,430 --> 00:51:52,270
>> Sawa.

935
00:51:52,270 --> 00:51:55,080
Sasa kwa bahati mbaya, kwa
Dakika saba iliyopita,

936
00:51:55,080 --> 00:51:57,410
Nina kuweka kupiga
akili yako kidogo.

937
00:51:57,410 --> 00:52:00,230
Hivyo naomba kuonyesha
baadhi ya mambo mengine pia.

938
00:52:00,230 --> 00:52:03,710
>> Tumekuwa umeonyesha wewe wazo hili la
kuwa kazi hizi bila majina,

939
00:52:03,710 --> 00:52:07,040
kufungwa hizi kwamba kuruhusu
aina ya kupitisha kazi kuzunguka.

940
00:52:07,040 --> 00:52:08,100
Unaweza kurudi kwao.

941
00:52:08,100 --> 00:52:09,490
Unaweza kuendesha yao.

942
00:52:09,490 --> 00:52:11,790
Unaweza kufanya kila aina ya mambo mambo.

943
00:52:11,790 --> 00:52:14,850
>> Lakini jambo moja nyingine kwamba
hutokea kwa kuwa na manufaa

944
00:52:14,850 --> 00:52:19,740
ni uwezo wa, kinyume
kwa kurudi kazi hizo

945
00:52:19,740 --> 00:52:25,146
katika kazi, kupita kazi
kama parameter kwa kazi nyingine.

946
00:52:25,146 --> 00:52:30,430
Unaweza kuwa na mawazo vizuri kwa nini Duniani
ingekuwa nataka kufanya kitu kama hicho?

947
00:52:30,430 --> 00:52:33,660
>> Naam, hebu kusema kwamba nataka
kuchukua operator huu kwamba mimi

948
00:52:33,660 --> 00:52:40,260
kazi kwa bidii ili kujenga na kuomba
kwa rundo la idadi tofauti

949
00:52:40,260 --> 00:52:41,770
katika safu.

950
00:52:41,770 --> 00:52:46,700
Hivyo katika kesi hii nina safu ya
integers-- 1, 4, 7, 2, 5, 10, 56.

951
00:52:46,700 --> 00:52:48,080
Na mimi wanataka mara mbili yao yote.

952
00:52:48,080 --> 00:52:50,430
Njia ambayo tunataka kawaida
kufanya hivyo ni kuandika tu

953
00:52:50,430 --> 00:52:53,440
rahisi kwa kitanzi kwamba
iterates juu wote

954
00:52:53,440 --> 00:52:57,140
na kufanya aina fulani ya
operesheni za mraba juu yao,

955
00:52:57,140 --> 00:53:02,700
inputting maadili hayo mapya ndani ya mwezi
kutofautiana, au tuseme, safu mpya hapa.

956
00:53:02,700 --> 00:53:07,370
Na thamani ya pato la
Matokeo yake ni kisha wote wa arrays hizo,

957
00:53:07,370 --> 00:53:10,200
au tuseme wale wote
mambo sasa squared.

958
00:53:10,200 --> 00:53:12,680
>> Na tunaweza kufanya hivyo
Jambo kwa cubing hilo,

959
00:53:12,680 --> 00:53:15,360
lakini kidogo kengele kengele
lazima kuwa kwenda mbali

960
00:53:15,360 --> 00:53:17,360
akisema kwamba labda kuna
baadhi ya njia kwamba tunataka

961
00:53:17,360 --> 00:53:19,860
kuwa na uwezo wa kurahisisha hii kidogo.

962
00:53:19,860 --> 00:53:21,130
Na kwa kweli kuna.

963
00:53:21,130 --> 00:53:25,320
Nini kama tunaweza kujenga
kazi ambayo inaruhusu sisi

964
00:53:25,320 --> 00:53:28,350
kukubali, kama Predator, kazi?

965
00:53:28,350 --> 00:53:30,350
Hivyo katika kesi hii, kuchukua
tuangalie hoja hizi.

966
00:53:30,350 --> 00:53:33,220
Tunakwenda kukubali orodha ya mara mbili.

967
00:53:33,220 --> 00:53:35,030
Na kisha tunakwenda
kukubali kazi

968
00:53:35,030 --> 00:53:40,990
katika variable kuitwa f kwamba ni kwenda
kuchukua Double na kurudi mara mbili.

969
00:53:40,990 --> 00:53:43,320
Na pato zima
ya kazi hii nzima

970
00:53:43,320 --> 00:53:47,310
aitwaye mapper ni kwenda
kurudi safu kuitwa mara mbili.

971
00:53:47,310 --> 00:53:52,380
>> Nini hii itakuwa kisha naomba
kufanya ni iterate juu ya orodha hiyo

972
00:53:52,380 --> 00:53:56,350
na kufanya kitu kimoja, lakini sasa
kuomba kazi ambayo kila

973
00:53:56,350 --> 00:53:58,970
maadili ya mtu binafsi katika orodha hiyo.

974
00:53:58,970 --> 00:54:00,750
Hivyo mimi si kweli kujua nini f ni.

975
00:54:00,750 --> 00:54:02,010
Haijalishi kwangu.

976
00:54:02,010 --> 00:54:06,530
Lakini kwa muda mrefu kama inachukua katika Double,
hufanya baadhi operesheni juu yake,

977
00:54:06,530 --> 00:54:08,640
na kisha anarudi
Double, napenda kisha kuwa

978
00:54:08,640 --> 00:54:13,415
uwezo wa ramani kazi ambayo hela
kila kipengele moja katika orodha.

979
00:54:13,415 --> 00:54:16,270

980
00:54:16,270 --> 00:54:20,930
>> Na aina hii ya programu ni
aitwaye kazi juu ili,

981
00:54:20,930 --> 00:54:24,440
ambapo sisi ni kupita kazi
karibu kama vigezo

982
00:54:24,440 --> 00:54:26,430
na kufanya mambo na kazi.

983
00:54:26,430 --> 00:54:29,640
Ni aina ya kama kuchukua yote haya
mawazo ambayo tumejifunza katika CS50

984
00:54:29,640 --> 00:54:31,390
na kuwapeleka aina
ya ngazi ya pili.

985
00:54:31,390 --> 00:54:34,140
Na hii yote ni mambo CS51 style.

986
00:54:34,140 --> 00:54:37,080
Na hivyo tutaweza kwenda katika kina
zaidi katika madarasa kama hayo.

987
00:54:37,080 --> 00:54:38,930
>> Lakini hii pia ni
muhimu hapa kwa sababu sisi

988
00:54:38,930 --> 00:54:42,010
kuona mengi ya kazi
ambazo hutumika katika Swift

989
00:54:42,010 --> 00:54:45,590
kwamba kimsingi anafanya
huu, ambapo tuna

990
00:54:45,590 --> 00:54:48,300
idadi ya baadhi, baadhi safu ya idadi.

991
00:54:48,300 --> 00:54:50,850
Tunakwenda kupita kwamba
safu katika mapper yetu.

992
00:54:50,850 --> 00:54:55,770
Na sisi ni pia kwenda
kupita baadhi ya kazi, ambayo

993
00:54:55,770 --> 00:54:57,950
tumekuwa tayari kuelezwa hapa.

994
00:54:57,950 --> 00:54:59,690
Ni kwenda kuwa mraba.

995
00:54:59,690 --> 00:55:02,220
Na tunakwenda kisha
mraba wote wa wale idadi

996
00:55:02,220 --> 00:55:04,710
na kuhifadhi kwamba katika matokeo haya hapa.

997
00:55:04,710 --> 00:55:07,280

998
00:55:07,280 --> 00:55:11,000
>> Hivyo kesi hii tumekuwa inavyoelezwa yetu
kazi mwenyewe iitwayo mapper.

999
00:55:11,000 --> 00:55:15,370
Lakini jambo hili ni halisi,
kwa kweli, kujengwa katika Swift.

1000
00:55:15,370 --> 00:55:18,960
Kuna aina ya
kazi inayoitwa ramani.

1001
00:55:18,960 --> 00:55:21,520
Kuna kazi ramani,
kuna kupunguza kazi,

1002
00:55:21,520 --> 00:55:25,630
na kuna chujio kazi,
ambayo kimsingi kuomba kazi

1003
00:55:25,630 --> 00:55:30,782
kwa kila kipengele moja katika
orodha ya kurekebisha yao kwa namna fulani.

1004
00:55:30,782 --> 00:55:34,510
>> Watazamaji: Hivyo tangu wewe ni kubadilisha
data katika muundo mwingine

1005
00:55:34,510 --> 00:55:36,134
kupitia function--

1006
00:55:36,134 --> 00:55:37,050
DAN Armendáriz: Haki.

1007
00:55:37,050 --> 00:55:39,420
Yeah, hivyo kazi
kwamba sisi ni kukubali

1008
00:55:39,420 --> 00:55:41,790
ni kubadilisha data kwa namna fulani.

1009
00:55:41,790 --> 00:55:44,700
Katika kesi hiyo, sisi walikuwa ama
squaring, au tulikuwa cubing hilo,

1010
00:55:44,700 --> 00:55:50,060
au kweli, tunaweza kufanya
hakuna operesheni juu yake wakati wote.

1011
00:55:50,060 --> 00:55:54,150
>> Lakini napenda kuonyesha jinsi hii basi
ni kwenda kuangalia kwa vitendo.

1012
00:55:54,150 --> 00:55:56,681
Na tena, mimi nina mbio
muda kidogo. hivyo mimi nina

1013
00:55:56,681 --> 00:55:59,430
kwenda kuwa na uwezo wa kwenda juu ya mambo yote
ya chanzo kanuni hapa kwa undani zaidi.

1014
00:55:59,430 --> 00:56:00,721
Lakini Mimi moyo wa kufanya hivyo.

1015
00:56:00,721 --> 00:56:03,850
Tutaweza baada yake kwa haraka kama
iwezekanavyo baada ya majadiliano hayo.

1016
00:56:03,850 --> 00:56:07,610
>> Lakini kama wewe kuangalia hii,
kudhani kwamba tuna orodha ya namba,

1017
00:56:07,610 --> 00:56:10,260
safu ya idadi katika hii
kutofautiana kuitwa namba.

1018
00:56:10,260 --> 00:56:16,670
Kisha tunataka kufanya hii
filter operesheni juu ya namba hizo.

1019
00:56:16,670 --> 00:56:19,730
Hivyo kuchuja ni kubwa
Ili kazi hiyo

1020
00:56:19,730 --> 00:56:24,660
anapokea safu na pia kazi.

1021
00:56:24,660 --> 00:56:28,760
Na juu ya kila kipengele katika kwamba
safu, hufanya kazi hiyo.

1022
00:56:28,760 --> 00:56:31,990
>> Kama hiyo anarudi kazi
kweli, ni kuvaa bidhaa hiyo.

1023
00:56:31,990 --> 00:56:36,100
Kama kazi kwamba anarudi uongo,
Moto huo unatoa mbali bidhaa hiyo.

1024
00:56:36,100 --> 00:56:40,480
Na kisha kuirudisha orodha
kwamba ni kisha linaloundwa zote

1025
00:56:40,480 --> 00:56:44,360
ya vitu wale ambao wamekuwa kuchujwa.

1026
00:56:44,360 --> 00:56:47,150
>> Hivyo kwa maneno mwingine, hii ni
wazo moja, gradebook.

1027
00:56:47,150 --> 00:56:50,800
Tunaweza kuwa na aina ya darasa
ndani ya hii thamani aitwaye namba.

1028
00:56:50,800 --> 00:56:55,590
Inaweza kuwa 100, na 70, na
40, kadhalika na kadhalika.

1029
00:56:55,590 --> 00:56:59,110
Nini filter hii haina taarifa ni
kwamba hii ni kwamba sukari kisintaksia

1030
00:56:59,110 --> 00:57:01,310
kwa kazi bila majina.

1031
00:57:01,310 --> 00:57:05,980
Hii ni kazi bila majina akisema
kwamba parameter kwamba mimi nina kukubali

1032
00:57:05,980 --> 00:57:09,690
ni kwenda kuwa, ikiwa ni
ni mkubwa kuliko 70,

1033
00:57:09,690 --> 00:57:15,837
basi hii itakuwa kurudi kweli, kwa maana kwamba
bidhaa kwamba yatawekwa katika chujio hii.

1034
00:57:15,837 --> 00:57:17,920
Basi hebu kuwa kidogo
thabiti zaidi kuhusu hili.

1035
00:57:17,920 --> 00:57:25,760
Kama mimi na safu hii ya namba
na lina ya 100, 70, na 40,

1036
00:57:25,760 --> 00:57:29,730
Mimi kufanya filter hii
operesheni juu ya kila mmoja wa wale.

1037
00:57:29,730 --> 00:57:33,270
Hivyo kwamba moja ya kwanza ni thamani hii ya 100.

1038
00:57:33,270 --> 00:57:36,770
100 zaidi au sawa
70 Ni kweli, ambayo

1039
00:57:36,770 --> 00:57:41,950
ina maana kwamba 100 ni agizo katika
nakala hii mpya wa safu hii.

1040
00:57:41,950 --> 00:57:44,290
70 pia hupita.

1041
00:57:44,290 --> 00:57:46,020
Lakini 40 hana.

1042
00:57:46,020 --> 00:57:54,290
Kwa hiyo kile ni kurudi katika passingCount
ni safu ya vipengele 100 na 70--

1043
00:57:54,290 --> 00:57:57,410
100, comma, 70.

1044
00:57:57,410 --> 00:57:59,870
Wale walikuwa wawili tu
vitu kwamba walikuwa agizo.

1045
00:57:59,870 --> 00:58:03,740
Na hivyo sababu mimi haraka akaenda kwa njia ya
mengi ya aina ya utaratibu ya juu

1046
00:58:03,740 --> 00:58:08,680
mambo ni kwa sababu hii ni kwamba kawaida
Jambo kwamba utaona katika Swift pretty

1047
00:58:08,680 --> 00:58:16,810
mara kwa mara, ni kufanya baadhi ya operesheni
kutumia hii bila majina kazi syntax.

1048
00:58:16,810 --> 00:58:18,450
>> Kuna baadhi ya mambo ya baridi.

1049
00:58:18,450 --> 00:58:24,730
Swichi ni kweli nguvu katika Swift,
I mean tu kama mambo, mambo yenye nguvu.

1050
00:58:24,730 --> 00:58:28,250
Unaweza kutumia kubadili, na
unaweza kweli kuyatumia

1051
00:58:28,250 --> 00:58:33,160
kwa safu, ambayo ni aina ya mambo,
na kufanya mambo ya dhana kama hiyo.

1052
00:58:33,160 --> 00:58:37,540
>> Lakini katika dakika chache zilizopita,
Nataka ruka mbele kabisa mbali

1053
00:58:37,540 --> 00:58:46,940
na kuonyesha mfano maalum ya jinsi
tunaweza kujenga katika iOS programu kutumia Swift.

1054
00:58:46,940 --> 00:58:49,040
Hivyo wakati wewe ni kufanya
hii, itabidi kuchukua

1055
00:58:49,040 --> 00:58:51,990
a kuangalia at-- juu ya Apple
nyaraka, wao

1056
00:58:51,990 --> 00:58:56,084
una mengi ya tutorials mzuri
kwa ajili ya kujenga maombi yako ya kwanza.

1057
00:58:56,084 --> 00:58:58,250
Na mimi moyo wa kufanya
kwamba kwa sababu wao kuchukua wewe

1058
00:58:58,250 --> 00:59:04,110
kupitia hatua zote za nini hasa kwa
click juu ya kuunda maombi iOS.

1059
00:59:04,110 --> 00:59:07,290
>> Lakini hapa tuna programu hii iOS.

1060
00:59:07,290 --> 00:59:10,960
Na ni programu pretty rahisi kweli.

1061
00:59:10,960 --> 00:59:13,840
Kama mimi kukimbia hii, napenda kuonyesha
wewe nini inaonekana kama.

1062
00:59:13,840 --> 00:59:19,480
Wote ni kimsingi gani ni
pulls kutoka internet JSON faili

1063
00:59:19,480 --> 00:59:22,300
kwamba mimi kuhifadhiwa kwenye kompyuta.

1064
00:59:22,300 --> 00:59:26,310
Na kwamba JSON faili
amefafanua picha kwamba kuruhusu

1065
00:59:26,310 --> 00:59:31,680
mimi kisha mzunguko kwa njia, juu ya yangu
programu, picha kutoka mtandao wa kompyuta yangu.

1066
00:59:31,680 --> 00:59:32,880
>> Hivyo nina hapa getNextImage.

1067
00:59:32,880 --> 00:59:37,100
Ni mizigo picha kutoka katika mtandao,
na kisha maonyesho hayo kwenye screen.

1068
00:59:37,100 --> 00:59:38,200
>> Hivyo ni pretty rahisi.

1069
00:59:38,200 --> 00:59:41,550
Lakini lengo hapa ni kuonyesha
jinsi tunaweza kuchanganya mambo

1070
00:59:41,550 --> 00:59:47,820
kutoka mwisho wa wiki chache ya CS50
ndani ya halisi iOS maombi.

1071
00:59:47,820 --> 00:59:53,140
Kwa maneno mengine, labda ni moja ya
mambo ambayo wewe unataka kufanya

1072
00:59:53,140 --> 00:59:56,340
ni kuwa na maombi iOS kwamba
anaweza kuvuta data kutoka kwa mtandao

1073
00:59:56,340 --> 00:59:59,070
na kuonyesha user baadhi ya habari.

1074
00:59:59,070 --> 01:00:03,130
Hiyo ni kabisa hatua
ya hii chanzo kanuni hapa.

1075
01:00:03,130 --> 01:00:07,890
>> Hivyo kuna mengi ya kusema kuhusu
jinsi ya kufanya maendeleo halisi iOS.

1076
01:00:07,890 --> 01:00:12,860
Kuna mengi ya mambo syntax
kwamba hatujaona bado kabisa

1077
01:00:12,860 --> 01:00:15,580
kama darasa, kile darasa kweli ni.

1078
01:00:15,580 --> 01:00:19,470
Tunaweza kwa kiasi kikubwa kupuuza
kwamba kwa wakati huu.

1079
01:00:19,470 --> 01:00:23,250
>> Lakini taarifa kwamba tuna zilizomo
ndani ya hii aina ya mambo

1080
01:00:23,250 --> 01:00:27,720
kuwa tumekuwa tayari kuona kama
kazi ambazo zina majina maalum.

1081
01:00:27,720 --> 01:00:32,650
Na wakati sisi kutoa wale
kazi zake majina sahihi

1082
01:00:32,650 --> 01:00:36,530
kwamba wanatarajiwa na iOS, kwa kweli
hii anahisi kidogo kichawi.

1083
01:00:36,530 --> 01:00:40,300
Lakini wakati kujenga
iOS maombi, kuna

1084
01:00:40,300 --> 01:00:47,590
ndiyo majina kazi maalum kwamba
walioitwa kwa simu yenyewe

1085
01:00:47,590 --> 01:00:52,440
kama maombi ni kupakia kujaribu
kujenga mchakato kwamba kweli

1086
01:00:52,440 --> 01:00:54,787
anaendesha maombi yako.

1087
01:00:54,787 --> 01:00:58,120
Hivyo tena, kuna mambo mengi ambayo mimi
kuwa na Gloss juu hapa ili na sisi

1088
01:00:58,120 --> 01:01:00,570
kuzungumza kuhusu suala hili mahsusi.

1089
01:01:00,570 --> 01:01:06,050
Lakini mimi moyo kuangalia labda
wengine iOS semina, lakini pia baadhi

1090
01:01:06,050 --> 01:01:09,290
ya tutorials online ambayo kufanya
kazi bora zaidi ya kuelezea

1091
01:01:09,290 --> 01:01:11,030
taarifa maalum.

1092
01:01:11,030 --> 01:01:15,760
>> Lakini tunaweza kuona michache ya mambo ambayo
ni ya kuvutia kutoka kificho hapa.

1093
01:01:15,760 --> 01:01:17,950
Taarifa kwamba tuna kama kauli.

1094
01:01:17,950 --> 01:01:20,400
Kwa njia, moja muhimu
Jambo kuhusu kauli kama

1095
01:01:20,400 --> 01:01:24,860
ni kwamba mabano kuzunguka
Kujieleza Boolean ni hiari.

1096
01:01:24,860 --> 01:01:30,800
Lakini braces curly si hiari,
bila kujali jinsi chache au mistari mingi ya kificho

1097
01:01:30,800 --> 01:01:32,360
una katika ikiwa kauli.

1098
01:01:32,360 --> 01:01:38,670
Huwezi kuwa kama kauli
bila braces curly katika Swift.

1099
01:01:38,670 --> 01:01:41,000
>> Na hii ni, vizuri, aina ya silly.

1100
01:01:41,000 --> 01:01:43,910
Lakini kuna sababu za kihistoria kwa ajili hiyo.

1101
01:01:43,910 --> 01:01:46,180
Ni walidhani kuokoa kutoka mwenyewe.

1102
01:01:46,180 --> 01:01:49,899
Kama hii kwa mfano, huwezi
kuondoa braces curly kuzunguka kwamba

1103
01:01:49,899 --> 01:01:50,440
kama taarifa.

1104
01:01:50,440 --> 01:01:52,730
Wale ni kwa kweli inahitajika.

1105
01:01:52,730 --> 01:01:54,480
Hivyo Mimi moyo
tuangalie hii.

1106
01:01:54,480 --> 01:01:56,230
Lakini kuna moja zaidi
kujenga kwamba nataka

1107
01:01:56,230 --> 01:02:02,640
kuwaonyesha kuhusu Swift kwamba
ni mpya kwa Swift 2.0 ikilinganishwa

1108
01:02:02,640 --> 01:02:08,460
kwa matoleo ya zamani ya Swift,
ambayo ni yafuatayo.

1109
01:02:08,460 --> 01:02:11,620
Hebu angalia wapi mimi kuweka hapa?

1110
01:02:11,620 --> 01:02:16,630
>> Hivyo katika kazi hii inaitwa
fetchJSON, kazi hii

1111
01:02:16,630 --> 01:02:23,450
ina jukumu la kuunganisha kwamba JSON
faili kutoka URL, ambayo tu hivyo hutokea

1112
01:02:23,450 --> 01:02:26,310
kuwa mbio juu ya CS50 yangu IDE.

1113
01:02:26,310 --> 01:02:28,580
Mimi tu ya kuanza Apache,
kuweka JSON faili yangu huko,

1114
01:02:28,580 --> 01:02:32,110
na mimi nina uwezo wa kuvuta kwamba basi
data kutoka kwa mtandao kwa kutumia

1115
01:02:32,110 --> 01:02:36,430
kazi hii na URL hii,
ambayo hutolewa kwa njia ya simu.

1116
01:02:36,430 --> 01:02:40,490
Ni zinazotolewa na
maktaba kwamba matumizi wakati

1117
01:02:40,490 --> 01:02:43,140
unafanya baadhi iOS programu ya maendeleo.

1118
01:02:43,140 --> 01:02:49,690
>> Taarifa hapa kwamba kuna hii isiyo ya kawaida
syntactical kujenga aitwaye walinzi.

1119
01:02:49,690 --> 01:02:53,530
Na kwa kweli yote haya ni katika
Swift ni njia ya kuthibitisha

1120
01:02:53,530 --> 01:02:56,870
kwamba baadhi ya mambo na
alikutana kabla

1121
01:02:56,870 --> 01:03:00,000
kuendelea na mapumziko ya kazi.

1122
01:03:00,000 --> 01:03:04,260
Ili niweze kuwa, kwa kutumia
aina hii ya hiari,

1123
01:03:04,260 --> 01:03:10,530
Mimi naweza wamegundua URL na
mbio kazi hii NSURL

1124
01:03:10,530 --> 01:03:16,640
na kuhifadhi kwamba katika URL
mara kwa mara, na kisha kuangalia

1125
01:03:16,640 --> 01:03:20,820
ili kuona kama URL ilikuwa haina kabisa, kwa sababu
ilikuwa kwenda na kurudi aina ya hiari.

1126
01:03:20,820 --> 01:03:25,660
Na kama ilikuwa haina kabisa, kisha napenda
magazeti nje makosa na kisha kurudi.

1127
01:03:25,660 --> 01:03:29,970
>> Lakini badala yake, nini walinzi lets
sisi kufanya ni kuwa kitu sana,

1128
01:03:29,970 --> 01:03:34,550
lakini kuhakikisha kwamba ni
kweli kesi hiyo url

1129
01:03:34,550 --> 01:03:38,020
imekuwa vizuri kuweka na NSURL.

1130
01:03:38,020 --> 01:03:41,810
Na kama ni, basi ni
skips juu ya hili, na ni

1131
01:03:41,810 --> 01:03:46,110
itawawezesha kuendelea na
url baada ya kuelezwa vizuri.

1132
01:03:46,110 --> 01:03:48,830
Lakini ikiwa ni kesi hiyo
url ni vizuri defined,

1133
01:03:48,830 --> 01:03:52,550
kama kazi hii anarudi makosa
au nyingine jambo isiyotarajiwa

1134
01:03:52,550 --> 01:03:58,030
kweli hutokea, huu kujenga ulinzi
inaruhusu sisi kisha pato kwamba makosa

1135
01:03:58,030 --> 01:04:00,390
na kurudi mara moja.

1136
01:04:00,390 --> 01:04:00,890
Ndiyo?

1137
01:04:00,890 --> 01:04:04,839
>> Watazamaji: Hivyo ni aina
ya kama ikiwa kisha mwingine?

1138
01:04:04,839 --> 01:04:07,130
DAN Armendáriz: Ni aina ya
kama ikiwa kisha mwingine, ndiyo,

1139
01:04:07,130 --> 01:04:14,200
isipokuwa kwamba url hii ni kisha
inavyoelezwa kwa kila kitu hapa chini hii.

1140
01:04:14,200 --> 01:04:20,420
Kama itapita walinzi hii, basi ni
kwa kweli kujazwa na data

1141
01:04:20,420 --> 01:04:29,500
na inatumika katika iliyobaki
chanzo kanuni katika kazi yako.

1142
01:04:29,500 --> 01:04:33,790
Hivyo mimi mtuhumiwa kuwa wewe ni kwenda
kuanza kuona walinzi huu pia.

1143
01:04:33,790 --> 01:04:36,670
Na kukumbuka ya kwamba.

1144
01:04:36,670 --> 01:04:46,270
>> Hivyo kuangalia tu michache ya wengine
mambo, haki hii hapa ni nini,

1145
01:04:46,270 --> 01:04:53,377
unafikiri, tu kulingana na kile
sisi walikuwa wanazungumza juu kabla?

1146
01:04:53,377 --> 01:04:56,650
>> Watazamaji: Fikiria kutakuwa na kukimbia katika orodha?

1147
01:04:56,650 --> 01:04:59,100
>> DAN Armendáriz: Basi hiyo ni karibu.

1148
01:04:59,100 --> 01:05:02,360
Hii ni kazi ambayo sisi ni kufafanua.

1149
01:05:02,360 --> 01:05:07,240
Na sisi ni inputting kazi ambayo
kama hoja kwa kazi hii hapa.

1150
01:05:07,240 --> 01:05:09,120
>> Watazamaji: [inaudible] kama si nil.

1151
01:05:09,120 --> 01:05:11,470
Hivyo ni katika orodha, sawa?

1152
01:05:11,470 --> 01:05:15,450
>> DAN Armendáriz: Kama kosa ni si haina kabisa,
ili is-- hivyo nina kitabu.

1153
01:05:15,450 --> 01:05:18,060
Naam, hebu angalia, siwezi
kitabu kwa haki hapa.

1154
01:05:18,060 --> 01:05:23,161
kosa ni hoja kuwa ni kuwa
kupita kwa kazi hii bila majina.

1155
01:05:23,161 --> 01:05:24,410
Hii ni kazi bila majina.

1156
01:05:24,410 --> 01:05:25,480
Haina jina.

1157
01:05:25,480 --> 01:05:29,850
Lakini sisi ni kukubali hawa watatu
hoja, data, majibu, na makosa.

1158
01:05:29,850 --> 01:05:33,590
Na ni kwenda na kurudi ni batili, hivyo
siyo kwenda na kurudi kitu chochote.

1159
01:05:33,590 --> 01:05:37,910
Na hii ni yaliyomo
ya kazi hiyo.

1160
01:05:37,910 --> 01:05:41,961
Na kisha sisi kupata ndani ya kwamba
kazi kwa kila mmoja wa hoja hizi.

1161
01:05:41,961 --> 01:05:45,650

1162
01:05:45,650 --> 01:05:48,679
>> Hivyo ni kimbunga
ziara ya lugha.

1163
01:05:48,679 --> 01:05:50,470
Lakini natumaini na hii,
hopefully kama wewe kuchukua

1164
01:05:50,470 --> 01:05:54,490
Kuangalia baadhi ya tutorials
maalum kwa iOS maendeleo na Swift,

1165
01:05:54,490 --> 01:05:57,481
hasa kama wewe kwenda
Apple developer mtandao page--

1166
01:05:57,481 --> 01:05:59,980
wana mengi ya mzuri
tutorials kupata wewe kuanza.

1167
01:05:59,980 --> 01:06:05,010
Lakini pengine tu hii saa ya kuzungumza
kuhusu syntax yenyewe ametoa

1168
01:06:05,010 --> 01:06:08,760
wewe kutosha ya kupata ilianza na kwamba.

1169
01:06:08,760 --> 01:06:12,950
>> Sisi baada ya yote ya chanzo hiki
kificho kwenye tovuti semina

1170
01:06:12,950 --> 01:06:17,800
haraka iwezekanavyo, na pia slides
hivyo kuwa rejea kwa ajili ya wale wote.

1171
01:06:17,800 --> 01:06:20,530
Lakini bahati nzuri na miradi yako.

1172
01:06:20,530 --> 01:06:23,640
Na kuwashukuru wote sana kwa kuja.

1173
01:06:23,640 --> 01:06:26,990
>> [Makofi]

1174
01:06:26,990 --> 01:06:28,026