arrays - swift 的数组范围

Question

以下 python 代码的 swift 等价物是什么？

array =[ "a", "b", "c"]
print(array[1:])

( 上面的语句打印从第一个索引到数组末尾的每个元素。
输出 ['b', 'c'])

编辑
有没有一种方法可以在不使用 array.count 的情况下完成？因为 array.count 是多余的，如果我说想要第二个位置的每个元素

Answer 1

有了 Swift 4，有很多方法可以解决您的问题。根据您的需要，您可以选择以下六种模式中的一种。

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#1。使用数组 dropFirst()方法

let array = ["a", "b", "c"]
let arraySlice = array.dropFirst()
let newArray = Array(arraySlice)
print(newArray) // prints ["b", "c"]

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#2。使用数组 suffix(from:)方法

let array = ["a", "b", "c"]
let arraySlice = array.suffix(from: 1)
let newArray = Array(arraySlice)
print(newArray) // prints ["b", "c"]

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#3。使用数组 suffix(_:)方法

let array = ["a", "b", "c"]
let arraySlice = array.suffix(array.endIndex.advanced(by: -1))
// let arraySlice = array.suffix(array.count - 1) // also works
let newArray = Array(arraySlice)
print(newArray) // prints ["b", "c"]

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#4。使用数组 subscript(_:​)和 CountableRange

let array = ["a", "b", "c"]
let range = array.startIndex.advanced(by: 1) ..< array.endIndex
// let range = 1 ..< array.count // also works
let arraySlice = array[range]
let newArray = Array(arraySlice)
print(newArray) // prints ["b", "c"]

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#5。使用数组 subscript(_:​)和 CountableClosedRange

let array = ["a", "b", "c"]
let range = 1 ... array.count - 1 // also works
let arraySlice = array[range]
let newArray = Array(arraySlice)
print(newArray) // prints ["b", "c"]

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#6。使用数组 subscript(_:​)和 CountablePartialRangeFrom

let array = ["a", "b", "c"]
let range = 1...
let arraySlice = array[range]
let newArray = Array(arraySlice)
print(newArray) // prints ["b", "c"]