Swift-从数组中修剪元素，将整数字符串转换为整数 [英] Swift - pruning elements from an Array, converting integer strings to integers

问题描述

我有一个包含数字和空字符串的数组，例如["", "2", "4", "", "", "1", "2", ""].我想将其简化为一个数字列表，例如[2,4,1,2].

I have an array that contains numbers and empty strings, like ["", "2", "4", "", "", "1", "2", ""]. I would like to pare this down to a list of numbers, like [2,4,1,2].

我首先将其分为两个步骤，首先剥离空字符串，然后进行字符串到整数的转换.但是，我第一步的代码无法正常工作.

My first effort split this into two steps, first strip out the empty strings, then do the string-to-integer conversion. However, my code for step one isn't working as desired.

for (index,value) in tempArray.enumerate(){
    if value == ""  {
        tempArray.removeAtIndex(index)
    }
}

这会失败，我相信是因为它使用的是原始完整数组中的索引值，尽管在第一次删除后它们不再准确.

This fails, I believe because it is using the index values from the original, complete array, though after the first deletion they are not longer accurate.

什么是实现我的目标的更好方法，以及将所得的整数字符串数组转换为整数数组的最佳方法是什么?

What would be a better way to accomplish my goal, and what is the best way to convert the resulting array of integer strings to an array of integers?

推荐答案

借助Swift 2，我们可以利用flatMap和Int()的优势:

With Swift 2 we can take advantage of flatMap and Int():

let stringsArray = ["", "2", "4", "", "", "1", "2", ""]

let intsArray = stringsArray.flatMap { Int($0) }

print(intsArray)  // [2, 4, 1, 2]

说明:如果字符串不包含整数，则Int()返回nil，并且flatMap忽略nil并解包Int()返回的可选Int.

Explanation: Int() returns nil if the string does not contain an integer, and flatMap ignores nils and unwraps the optional Ints returned by Int().

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