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͍͍͔Β!Λ͑ʂ
f o r : 6 . & . * T X J G U
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}
var employedBy = "YUMEMI Inc."
var job = "iOS Tech Lead"
var favoriteLanguage = "Swift"
var twitter = "@lovee"
var qiita = "lovee"
var github = "el-hoshino"
var additionalInfo = """
อޢͨ͠ೣ͕ͷൃظʹಥೖͯ݁͠ߏେม
"""
final class Me: Developable, Talkable {
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4XJGUͰ!ͬͯ·͢ʁ
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ͪΖΜBoolసҎ֎Ͱ
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4XJGUʹ͓͚Δ!ͷओͳ͍ಓ˞
w Optionalͷڧ੍6OXSBQʢ*60ؚΉʣ
w ܕมͷڧ੍μϯΩϟετas!
w ྫ֎ॲཧͷڧ੍ྫ֎ແࢹtry!
˞#PPMసҎ֎
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ڞ௨ɿϓϩάϥϜ͕
Ϋϥογϡ͢ΔϦεΫ͕͋Δ
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!ΛΘͳ͍ํ͕҆શ
本当にそうか？
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͜ͷίʔυͬͯɺ҆શʁ
func doSomething() {
let image = UIImage(named: "ImageName") ?? UIImage()
// do something with image
}
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͜ͷίʔυͬͯɺ҆શʁ
func doSomething() {
guard let appDelegate = UIApplication
.shared.delegate as? AppDelegate else {
return
}
// do something with appDelegate
}
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͜ͷίʔυͬͯɺ҆શʁ
func doSomething(with data: Data) {
do {
let decoder = JSONDecoder()
let response = try decoder.decode(Response.self, from: data)
// do something with response
} catch {
debugPrint(error)
return
}
}
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ΞϓϦ͕Ϋϥογϡ͠ͳ͍͔Βɺ
҆શɻ
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ΞϓϦ͕Ϋϥογϡ͠ͳ͍͔Βɺ
҆શʜͳͷ͔ʁ
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ͦͦɺ҆શͬͯɺͳʹʁ
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ੲɺ0CK$͔Β4XJGUʹҠߦͨ࣌͠ͷ˞
w αʔό͔Βը૾σʔλͱදࣔαΠζΛऔಘ͢Δॲཧ͕͋ͬͨ
w αΠζσʔλ෯ߴͦ͞ΕͧΕ0CK$ͷίʔυͰintValueͰऔಘͯͨ͠
w 4XJGUԽ͢Δͱ͖Կߟ͑ͣʹas? Int ?? 0Ͱॲཧͯͨ͠
w ϦϦʔεޙɺҰ෦ͷը૾ͷΈΞεϖΫτൺ͕มΘͬͯ͠·ͬͨࣄ͕݅ൃੜ
w ௐࠪͨ͠Βɺαʔό͔Βؼ͖ͬͯͨσʔλ͕ͳ͔ͥจࣈྻσʔλͩͬͨͨ
Ίɺ0CK$ࣗಈมͯ͘͠Ε͕ͨ4XJGUܕʹݫ͍ͨ͠Ίࣗಈมͯ͘͠
Εͣɺ?? 0ʹΑͬͯ0͕ೖ͞Εͨ
w ෯0ߴ͞0ͷ߹σϑΥϧταΠζͰදࣔ͢Δॲཧ͕͋ͬͨͨΊɺςε
τσʔλͰಈ࡞֬ೝ͢Δͱ͖શ͘ؾ͔ͮͳ͔ͬͨ
˞࣮Ͱ͢
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Ϋϥογϡ͠ͳ͔͕ͬͨɺ
!Λආ͚Δ͋·Γɺ
ٯʹόάͷൃݟΛΒͤͨ
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ʮ҆શʯͳιʔείʔυɺ
όάΛຊ൪ϦϦʔεલʹ
ؾ͔ͮͤΔ͖ɻ
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͜ͷίʔυͬͯɺ҆શʁ
func doSomething() {
let image = UIImage(named: "ImageName") ?? UIImage()
// do something with image
}
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͜ͷίʔυͷํ͕ɺ҆શ
func doSomething() {
let image = UIImage(named: "ImageName")!
// do something with image
}
όϯυϧʹೖͬͯͳ͍ͱ͍͚ͳ͍ͣͷ
ը૾Ϧιʔε͔ͩΒɺ
ສ͕Ұೖͬͯͳ͔ͬͨΒͦΕόάͳͷͰ
ಈ࡞֬ೝͰΫϥογϡͯ͘͠Εͨํ͕
ؾ͖͍͢
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͜ͷίʔυͬͯɺ҆શʁ
func doSomething() {
guard let appDelegate = UIApplication
.shared.delegate as? AppDelegate else {
return
}
// do something with appDelegate
}
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͜ͷίʔυͷํ͕ɺ҆શ
func doSomething() {
let appDelegate = UIApplication.shared.delegate as! AppDelegate
// do something with appDelegate
}
ϓϩδΣΫτͷ࡞Γ͕
͜ͷΑ͏ʹͳͬͯΔͣͳͷͰɺ
ສ͕Ұ͜ΕͰμϯΩϟετͰ͖ͳ͔ͬͨΒ
ઈରϓϩάϥϜ͕Կ͔ؒҧͬͯΔ͔ͣͩΒɺ
ಈ࡞֬ೝͰΫϥογϡͯ͘͠Εͨํ͕
ؾ͖͍͢
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!Λ͏͖ॴͰͬͨํ͕ɺ
όάͷૣظൃݟʹͭͳ͕Γɺ
Ή͠Ζ҆қͳѲΓ௵͠ΑΓ҆શɻ
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વɺཚ༻͍͚ͯ͠ͳ͍ɻ
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͜ͷίʔυͬͯɺ҆શʁ
func doSomething(with data: Data) {
do {
let decoder = JSONDecoder()
let response = try decoder.decode(Response.self, from: data)
// do something with response
} catch {
debugPrint(error)
return
}
}
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͜ͷίʔυͷํ͕ɺ҆શ
func doSomething(with data: Data) {
do {
let decoder = JSONDecoder()
let response = try decoder.decode(Response.self, from: data)
// do something with response
} catch {
assertionFailure("\(error)")
return
}
} ԾʹαʔόͷσʔλͱҰக͠ͳ͔ͬͨΒ
BTTFSUJPO'BJMVSFʹΑͬͯ
σόοάϏϧυ͚ͩΫϥογϡͯ͠
όάΛૣظൃݟ͠ɺ
ຊ൪ͷϦϦʔεϏϧυʹӨڹͳ͠ɻ
ʢͪΖΜ͜͜ͰߋʹΤϥʔΞϥʔτΛ
Ϣʔβʹදࣔͤͨ͞Βͳ͓ྑ͠ʣ
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͜ͷίʔυɺ͕͢͞ʹ҆શͰͳ͍
func doSomething(with data: Data) {
let decoder = JSONDecoder()
let response = try! decoder.decode(Response.self, from: data)
// do something with response
}
ສ͕Ұαʔόଆ͕όάΛى͜Γ
ຊདྷͷ༷ͱҧ͏ܕͷϨεϙϯε͕
ؼ͖ͬͯͨΒ
ΞϓϦ͕ଈΫϥογϡ͢ΔͷͰ
ྲྀੴʹྑ͘ͳ͍
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5*14ᶃ
w ͦΕͰΓͲ͏ͯ͠ຊ൪ϦϦʔεͰΫϥογϡ
ͯ͠ཉ͘͠ͳ͍ɻԿ͔ํ๏͋Δʁ
w assertionFailureΛ͑ɺσόοάϏϧυͩ
͚ΫϥογϡͰ͖ΔͷͰɺͥͻ׆༻͠·͠ΐ͏ɻ
w ྫɿ
let image = UIImage(named: "ImageName") ?? {
assertionFailure("ImageName not found")
return UIImage()
}()
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5*14ᶄ
w ଞʹͲ͔͜ੵۃతʹ!Λͬͨํ͕໘͋Δʁ
w ςετίʔυΉ͠ΖੵۃతʹόάΛؾ͖͍ͨ͠
ຊ൪ΞϓϦʹҰӨڹ͠ͳ͍ͷͰɺੵۃతʹ!Λ
͑Δ͜ͱ͕ଟ͍Ͱ͢ɻ
w ͨͩ͠Ϋϥογϡ͢Δͱޙଓͷίʔυಈ͔ͳ͘
ͳΔͷͰɺॴʹΑͬͯXCTFailΛͬͨํ
͕͍͍͜ͱ͋Γ·͢
w 1MBZHSPVOEͱ͔ͷຊ൪ΞϓϦؔͳࣗ͘Ͱखܰ
ͳಈ࡞֬ೝ͍ͨ࣌ͪ͠ΖΜੵۃతʹͬͯΑ͠
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!ΛաʹڪΕͣʹ
͏·͘׆༻ͯ͠
όάΛૣظʹ௵͠·͠ΐ͏