我的应用程序在 "return nil" 时关闭,我该如何解决? | Swift
My app closes when "return nil", how can I fix it? | Swift
我想使用正则表达式,但我不会
class Regex {
let pattern: String
let internalExpression: NSRegularExpression
init?(_ pattern: String) {
do {
self.internalExpression = try NSRegularExpression(pattern: pattern, options: .CaseInsensitive)
} catch {
print(error)
}
return nil
}
func test(input: String) -> Bool {
let matches = self.internalExpression.matchesInString(input, options: [], range:NSMakeRange(0, input.characters.count))
return matches.count > 0
}
}
您的代码无法编译(常量 'self.pattern' 在初始化之前使用 )并且您可能不想 return nil
即使成功
class Regex {
let pattern: String
let internalExpression: NSRegularExpression
init?(_ pattern: String) {
do {
self.pattern = pattern
self.internalExpression = try NSRegularExpression(pattern: pattern, options: .CaseInsensitive)
} catch {
print(error)
return nil
}
}
func test(input: String) -> Bool {
let matches = self.internalExpression.matchesInString(input, options: [], range:NSMakeRange(0, input.characters.count))
return matches.count > 0
}
}
我想使用正则表达式,但我不会
class Regex {
let pattern: String
let internalExpression: NSRegularExpression
init?(_ pattern: String) {
do {
self.internalExpression = try NSRegularExpression(pattern: pattern, options: .CaseInsensitive)
} catch {
print(error)
}
return nil
}
func test(input: String) -> Bool {
let matches = self.internalExpression.matchesInString(input, options: [], range:NSMakeRange(0, input.characters.count))
return matches.count > 0
}
}
您的代码无法编译(常量 'self.pattern' 在初始化之前使用 )并且您可能不想 return nil
即使成功
class Regex {
let pattern: String
let internalExpression: NSRegularExpression
init?(_ pattern: String) {
do {
self.pattern = pattern
self.internalExpression = try NSRegularExpression(pattern: pattern, options: .CaseInsensitive)
} catch {
print(error)
return nil
}
}
func test(input: String) -> Bool {
let matches = self.internalExpression.matchesInString(input, options: [], range:NSMakeRange(0, input.characters.count))
return matches.count > 0
}
}