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技术社区[云栖]
Swift下标
还记得字典吗?
var numberOfLegs= ["spider": 8,"ant": 6, "cat":4] numberOfLegs["bird"]= 2
["bird"]就是下标 下标可以在类和结构体中定义。
定义下标
subscript(index: Int) -> Int {
get {
//return anappropriate subscript value here
}
set(newValue) {
// perform a suitable settingaction here
}
}
只读下标
subscript(index: Int) -> Int {
//return anappropriate subscript value here
}
实例:
struct TimesTable {
let multiplier: Int
subscript(index: Int) ->Int {
return multiplier * index
}
}
let threeTimesTable = TimesTable(multiplier: 3)
println("sixtimes three is \(threeTimesTable[6])")
// prints"six times three is 18"
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最后更新:2017-04-03 06:03:10