在Swift中，如何基于另一个数组对一个数组进行排序? [英] In Swift how can I sort one array based on another array?

问题描述

在Swift中，说我有两个数组:

In Swift, say I have two arrays:

var array1: [Double] = [1.2, 2.4, 20.0, 10.9, 1.5]
var array2: [Int] = [1, 0, 2, 0, 3]

现在，我想按升序对array1进行排序，并相应地重新索引array2，以便获得

Now, I want to sort array1 in ascending order and reindex array2 accordingly so that I get

array1 = [1.2, 1.5, 2.4, 10.9, 20.4]
array2 = [1, 3, 0, 0, 2]

是否有使用Swift函数或语法执行此操作的简单方法?

Is there a simple way to do this using Swift functions or syntax?

我知道我可以构建一个函数来执行此操作并可以跟踪索引，但是我很好奇是否存在更优雅的解决方案.

I know I can build a function to do it and can keep track of indices, but I'm curious if there is a more elegant solution.

推荐答案

let array1: [Double] = [1.2, 2.4, 20.0, 10.9, 1.5]
let array2: [Int] = [1, 0, 2, 0, 3]

// use zip to combine the two arrays and sort that based on the first    
let combined = zip(array1, array2).sorted {$0.0 < $1.0}
print(combined) // "[(1.2, 1), (1.5, 3), (2.4, 0), (10.9, 0), (20.0, 2)]"

// use map to extract the individual arrays    
let sorted1 = combined.map {$0.0}
let sorted2 = combined.map {$0.1}

print(sorted1)  // "[1.2, 1.5, 2.4, 10.9, 20.0]"
print(sorted2)  // "[1, 3, 0, 0, 2]"

---

将两个以上的数组排序在一起

如果要对3个或更多数组进行排序，则可以sort其中一个数组及其offset，使用map提取offsets，然后使用map进行排序其他数组:

If you have 3 or more arrays to sort together, you can sort one of the arrays along with its offsets, use map to extract the offsets, and then use map to order the other arrays:

let english = ["three", "five", "four", "one", "two"]
let ints = [3, 5, 4, 1, 2]
let doubles = [3.0, 5.0, 4.0, 1.0, 2.0]
let roman = ["III", "V", "IV", "I", "II"]

// Sort english array in alphabetical order along with its offsets
// and then extract the offsets using map
let offsets = english.enumerated().sorted { $0.element < $1.element }.map { $0.offset }

// Use map on the array of ordered offsets to order the other arrays
let sorted_english = offsets.map { english[$0] }
let sorted_ints = offsets.map { ints[$0] }
let sorted_doubles = offsets.map { doubles[$0] }
let sorted_roman = offsets.map { roman[$0] }

print(sorted_english)
print(sorted_ints)
print(sorted_doubles)
print(sorted_roman)

输出:

["five", "four", "one", "three", "two"]
[5, 4, 1, 3, 2]
[5.0, 4.0, 1.0, 3.0, 2.0]
["V", "IV", "I", "III", "II"]

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