Swift-对数组中每个字符串中的字符进行排序 [英] Swift - sorting characters in each string in an array

问题描述

因此，此问题是此问题的后续内容: swift字符串排列允许使用相同的字符串

So this question is a follow up to this one: swift string permutations allowing the same strings

在那里，我询问了我可以使用一组定义的字符串进行的所有可能的突变.我接下来要做的是过滤出具有相同组合但顺序不同的所有结果.

There, I asked about all possible mutations that I can make with a defined set of strings. What I am trying to do next is to filter out all results that have the same combination, but in a different order.

因此，如果输入为:["AB", "AC", "CA", "CB"]，则输出应为["AB", "AC", "CB"]，因为"AC"和"CA"具有相同的构造块.

So if the input is: ["AB", "AC", "CA", "CB"], the output should be ["AB", "AC", "CB"], since "AC" and "CA" have the same building blocks.

所以我的想法是先按字母顺序对每个字符串进行排序，然后再创建一个Set.

So my thought was to first sort each string alphabetically, and maybe then create a Set.

我已经停留在第一部分了:(

I am already stuck on the first part :(

let array = ["AB", "AC", "DC", "CA", "CB"]
print(type(of: array))
print(array)

let sortedArray = array.map{ $0.sorted() }
print(type(of: sortedArray))
print(sortedArray)

输出为:

Array<String>
["AB", "AC", "DC", "CA", "CB"]
Array<Array<Character>>
[["A", "B"], ["A", "C"], ["C", "D"], ["A", "C"], ["B", "C"]]

虽然我希望使用sortedArray:

While I expected for the sortedArray:

["AB", "AC", "CD", "AC", "BC"]

然后我想将各个字符串重新组合在一起:

Then I thought to join the individual strings back together:

print(array.map{ $0.joined() } )

产生ambiguous reference to member 'joined()'

但是我不知道如何解决这个问题.

But how to fix this I don't understand.

我也看到了这一点:将字符串中的字符快速排序其中使用以下代码:

I also saw this one: swift sort characters in a string where the following code is used:

var nonSortedString = "5121"
var sortedString = String(Array(nonSortedString.characters).sort())

但是我没有看到如何使用map和朋友(转换为Swift 4之后)应用它

But I don't see how to apply that using map and friends (after converting to Swift 4)

任何帮助表示赞赏.

推荐答案

如果要获取字符串，请对其字符进行排序，然后从中构建新的字符串，在Swift 4中，您可以:

If you want to take a string, sort its characters, and build a new string from that, in Swift 4 you can:

let string = "foobar"

let sortedString = String(string.sorted())

结果是:

讨厌"

因此，回到您的原始问题，您可以将字符串(是排列的集合)带到您的手中，并构建如下所示的组合排序数组:

So, going back to your original problem, you can take you strings, which are a collection of permutations, and build a sorted array of combinations like so:

let permutations = ["AB", "AC", "DC", "CA", "CB"]

// build set of combinations where each string has, itself, been sorted alphabetically

let combinations = Set(permutations.map { String($0.sorted()) })

// convert set (which removed duplicates) back to an array and sort it

let result = Array(combinations).sorted()

结果是:

["AB"，"AC"，"BC"，"CD"]

["AB", "AC", "BC", "CD"]

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