如何根据另一个数组的排序顺序对多个数组进行排序

Question

我有多个数组，我想根据其中一个的排序顺序对所有数组进行排序，如下所示：

var myArr = ["b", "a", "c"]
var myArr2 = ["letter b", "letter a", "letter c"]
var myArr3 = ["b is the second letter", "a is the first letter", "c is the third letter"]

func sortMultipleArraysBasedOnOne(alphabeticallyArray:Array, arrays:[Array]){
  //order myArr alphabetically
  for array in arrays{
    //change all arrays indexes like in myArr
  }
}

sortMultipleArraysBasedOnOne(myArr, [myArr2, myArr3])

我希望函数执行后，数组将如下所示：

myArr = ["a", "b", "c"]
myArr2 = ["letter a", "letter b", "letter c"]
myArr3 = ["a is the first letter", "b is the second letter", "c is the third letter"]

Answer 1

您可以执行以下操作：首先根据键控数组的索引的索引对它们进行索引的值对它们进行排序，然后使用PermutationGenerator：

let myArr = ["b", "a", "c"]
let myArr2 = ["letter b", "letter a", "letter c"]
let myArr3 = ["b is the second letter", "a is the first letter", "c is the third letter"]

func sortByKeyArray(keyArray: [String], valuesArrays: [[String]]) -> [[String]] {

    precondition(reduce(valuesArrays, true) { $0.0 && ($0.1.count == keyArray.count)},
        "Arrays all need to be the same length")


    let permutation = sorted(indices(keyArray)) {
        keyArray[$0] < keyArray[$1]
    }

    return valuesArrays.map {
        Array(PermutationGenerator(elements: $0, indices: permutation))
    }
}

sortByKeyArray(myArr, [myArr2, myArr3])
// returns [["letter a", "letter b", "letter c"], ["a is the first letter", "b is the second letter", "c is the third letter"]]

如果要在任何类型的集合上使它通用（但仍以与std lib集合算法相同的样式返回数组）：

func sortByKeyingCollection<C: CollectionType, D: SequenceType 
  where D.Generator.Element == C, 
        C.Index: RandomAccessIndexType, 
        C.Generator.Element: Comparable>
(key: C, values: D) -> [[C.Generator.Element]] {

    let permutation = sorted(indices(key)) {
        key[$0] < key[$1]
    }

    return map(values) {
        Array(PermutationGenerator(elements: $0, indices: permutation))
    }
}

以及带有自定义比较器的版本：

func sortByKeyingCollection<C: CollectionType, D: SequenceType where D.Generator.Element == C, C.Index: RandomAccessIndexType>(key: C, values: D, isOrderedBefore: (C.Generator.Element,C.Generator.Element)->Bool) -> [[C.Generator.Element]] {

    let permutation = sorted(indices(key)) {
        isOrderedBefore(key[$0],key[$1])
    }

    return map(values) {
        Array(PermutationGenerator(elements: $0, indices: permutation))
    }
}


sortByKeyingCollection(myArr, [myArr2, myArr3], >)
sortByKeyingCollection(myArr, [myArr2, myArr3], lexicographicalCompare)
sortByKeyingCollection(myArr, [myArr2, myArr3]) { dropFirst($0) < dropFirst($1) }