同时迭代两个数组

Question

我是Swift的新手。我一直在做Java编程。我有一个在Swift中编写代码的场景。

以下代码使用Java。我需要在Swift中为以下场景编写代码

// With String array - strArr1
String strArr1[] = {"Some1","Some2"}

String strArr2[] = {"Somethingelse1","Somethingelse2"}

for( int i=0;i< strArr1.length;i++){
    System.out.println(strArr1[i] + " - "+ strArr2[i]);
}

我在swift中有几个数组

var strArr1: [String] = ["Some1","Some2"]
var strArr2: [String] = ["Somethingelse1","Somethingelse2"]

for data in strArr1{
    println(data)
}

for data in strArr2{
    println(data)
}
// I need to loop over in single for loop based on index.

请您根据索引

提供有关循环语法的帮助

Answer 1

您可以使用zip()创建 来自两个给定序列的一对序列：

let strArr1 = ["Some1", "Some2"]
let strArr2 = ["Somethingelse1", "Somethingelse2"]

for (e1, e2) in zip(strArr1, strArr2) {
    print("\(e1) - \(e2)")
}

序列仅枚举给定序列/数组的“共同元素”。如果他们有不同的长度，那么额外的 简单地忽略较长数组/序列的元素。

Answer 2

试试这个：

zip([0,2,4,6], [1,3,5,7]).forEach {
    print($0,$1)
}

zip([0,2,4,6], [1,3,5,7]).forEach {
    print($0.0,$0.1)
}

Answer 3

您还可以在一个数组上enumerate并使用索引查看第二个数组：

Swift 1.2：

for (index, element) in enumerate(strArr1) {
    println(element)
    println(strArr2[index])
}

斯威夫特2：

for (index, element) in strArr1.enumerate() {
    print(element)
    print(strArr2[index])
}

斯威夫特3：

for (index, element) in strArr1.enumerated() {
    print(element)
    print(strArr2[index])
}

Answer 4

使用Swift 5，您可以使用以下4种Playground代码之一来解决您的问题。

---

＃1。使用zip(_:_:)函数

在最简单的情况下，您可以使用zip(_:_:)创建初始数组中元素对的新序列（元组）。

let strArr1 = ["Some1", "Some2", "Some3"]
let strArr2 = ["Somethingelse1", "Somethingelse2"]

let sequence = zip(strArr1, strArr2)

for (el1, el2) in sequence {
    print("\(el1) - \(el2)")
}

/*
 prints:
 Some1 - Somethingelse1
 Some2 - Somethingelse2
 */

---

＃2。使用Array的{​​{3}}方法和一个while循环

使用简单的while循环和迭代器，同时遍历两个数组也很容易：

let strArr1 = ["Some1", "Some2", "Some3"]
let strArr2 = ["Somethingelse1", "Somethingelse2"]

var iter1 = strArr1.makeIterator()
var iter2 = strArr2.makeIterator()

while let el1 = iter1.next(), let el2 = iter2.next() {
    print("\(el1) - \(el2)")
}

/*
 prints:
 Some1 - Somethingelse1
 Some2 - Somethingelse2
 */

---

＃3。使用符合makeIterator()

的自定义类型

在某些情况下，您可能需要创建自己的类型，以将姓名首字母数组的元素配对。通过使您的类型符合IteratorProtocol，可以实现此目的。请注意，通过使您的类型也符合Sequence协议，您可以在for循环中直接使用其实例：

struct TupleIterator: Sequence, IteratorProtocol {

    private var firstIterator: IndexingIterator<[String]>
    private var secondIterator: IndexingIterator<[String]>

    init(firstArray: [String], secondArray: [String]) {
        self.firstIterator = firstArray.makeIterator()
        self.secondIterator = secondArray.makeIterator()
    }

    mutating func next() -> (String, String)? {
        guard let el1 = firstIterator.next(), let el2 = secondIterator.next() else { return nil }
        return (el1, el2)
    }

}

let strArr1 = ["Some1", "Some2", "Some3"]
let strArr2 = ["Somethingelse1", "Somethingelse2"]

let tupleSequence = TupleIterator(firstArray: strArr1, secondArray: strArr2)

for (el1, el2) in tupleSequence {
    print("\(el1) - \(el2)")
}

/*
 prints:
 Some1 - Somethingelse1
 Some2 - Somethingelse2
 */

---

＃4。使用IteratorProtocol

作为上一个示例的替代方法，您可以使用AnyIterator。以下代码显示了它在Array扩展方法中的可能实现：

extension Array {

    func pairWithElements(of array: Array) -> AnyIterator<(Element, Element)> {
        var iter1 = self.makeIterator()
        var iter2 = array.makeIterator()

        return AnyIterator({
            guard let el1 = iter1.next(), let el2 = iter2.next() else { return nil }
            return (el1, el2)
        })
    }

}

let strArr1 = ["Some1", "Some2", "Some3"]
let strArr2 = ["Somethingelse1", "Somethingelse2"]

let iterator = strArr1.pairWithElements(of: strArr2)

for (el1, el2) in iterator {
    print("\(el1) - \(el2)")
}

/*
 prints:
 Some1 - Somethingelse1
 Some2 - Somethingelse2
 */

Answer 5

如果您仍想使用Range，则可以使用for in。

var strArr1: [String] = ["Some1","Some2"]
var strArr2: [String] = ["Somethingelse1","Somethingelse2"]

for i in Range(start: 0, end: strArr1.count) {
    println(strArr1[i] + " - " + strArr2[i])
}

Answer 6

> Incase of unequal count 

let array1 = ["some1","some2"]
let array2 = ["some1","some2","some3"]

var iterated = array1.makeIterator()
let finalArray = array2.map({ 
                 let itemValue = iterated.next()
                 return "\($0)\(itemValue != nil ? "-"+itemValue! : EmptyString)" })

//结果：[“ some1-some1”，“ some2-some2”，“ some3”]

Answer 7

for(var i = 0; i < strArr1.count ; i++)
{
    println(strArr1[i] + strArr2[i])
}

应该这样做。从来没有使用过swift，所以一定要测试。

  

更新到最近的Swift语法

for i in 0..< strArr1.count {
    print(strArr1[i] + strArr2[i])
}