来自Index Range Swift的新数组 [英] New Array from Index Range Swift

问题描述

我该怎么做?从数组中获取前n个元素:

How can I do something like this? Take the first n elements from an array:

newNumbers = numbers[0..n]

当前出现以下错误:

error: could not find an overload for 'subscript' that accepts the supplied arguments

这是我正在使用的功能.

Here is the function that I'm working in.

func aFunction(numbers: Array<Int>, position: Int) -> Array<Int> {
    var newNumbers = numbers[0...position]
    return newNumbers
}

推荐答案

这对我有用:

var test = [1, 2, 3]
var n = 2
var test2 = test[0..<n]

您的问题可能在于您如何声明数组的开始.

Your issue could be with how you're declaring your array to begin with.

要修复功能，必须将Slice强制转换为数组:

To fix your function, you have to cast your Slice to an array:

func aFunction(numbers: Array<Int>, position: Int) -> Array<Int> {
    var newNumbers = Array(numbers[0..<position])
    return newNumbers
}

// test
aFunction([1, 2, 3], 2) // returns [1, 2]

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