如何将Swift数组转换为字符串？

本文翻译自：How do I convert a Swift Array to a String?

I know how to programmatically do it, but I'm sure there's a built-in way... 我知道如何以编程方式进行操作，但是我敢肯定有一种内置方法...

Every language I've used has some sort of default textual representation for a collection of objects that it will spit out when you try to concatenate the Array with a string, or pass it to a print() function, etc. Does Apple's Swift language have a built-in way of easily turning an Array into a String, or do we always have to be explicit when stringifying an array? 我使用的每种语言都有一组对象的默认文本表示形式，当您尝试将Array与字符串连接起来或将其传递给print（）函数时，它将吐出。Apple的Swift语言是否可以有一种轻松地将数组转换为字符串的内置方法，还是在对数组进行字符串化时始终必须明确？

#1楼

参考：https://stackoom.com/question/1kMn3/如何将Swift数组转换为字符串

#2楼

If the array contains strings, you can use the String 's join method: 如果数组包含字符串，则可以使用String的join方法：

var array = ["1", "2", "3"]

let stringRepresentation = "-".join(array) // "1-2-3"

In Swift 2 : 在Swift 2中 ：

var array = ["1", "2", "3"]

let stringRepresentation = array.joinWithSeparator("-") // "1-2-3"

This can be useful if you want to use a specific separator (hypen, blank, comma, etc). 如果要使用特定的分隔符（连字符，空格，逗号等），这可能很有用。

Otherwise you can simply use the description property, which returns a string representation of the array: 否则，您可以简单地使用description属性，该属性返回数组的字符串表示形式：

let stringRepresentation = [1, 2, 3].description // "[1, 2, 3]"

Hint: any object implementing the Printable protocol has a description property. 提示：任何实现Printable协议的对象都具有description属性。 If you adopt that protocol in your own classes/structs, you make them print friendly as well 如果您在自己的类/结构中采用该协议，则也使它们易于打印

In Swift 3 在Swift 3中

• join becomes joined , example [nil, "1", "2"].flatMap({$0}).joined() join变得joined ，例如[nil, "1", "2"].flatMap({$0}).joined()
• joinWithSeparator becomes joined(separator:) (only available to Array of Strings) joinWithSeparator变为joinWithSeparator joined(separator:) （仅适用于字符串数组）

In Swift 4 在Swift 4中

var array = ["1", "2", "3"]
array.joined(separator:"-")

#3楼

The Swift equivalent to what you're describing is string interpolation. 与您描述的Swift等效的是字符串插值。 If you're thinking about things like JavaScript doing "x" + array , the equivalent in Swift is "x\\(array)" . 如果您考虑使用JavaScript做"x" + array类的事情，那么Swift中的等效项就是"x\\(array)" 。

As a general note, there is an important difference between string interpolation vs the Printable protocol. 作为一般说明，字符串插值与Printable协议之间存在重要区别。 Only certain classes conform to Printable . 仅某些类符合Printable 。 Every class can be string interpolated somehow. 每个类都可以以某种方式插入字符串。 That's helpful when writing generic functions. 这在编写泛型函数时很有用。 You don't have to limit yourself to Printable classes. 您不必仅限于Printable类。

#4楼

Swift 2.0 Xcode 7.0 beta 6 onwards uses joinWithSeparator() instead of join() : Swift 2.0 Xcode 7.0 beta 6及更高版本使用joinWithSeparator()而不是join() ：

var array = ["1", "2", "3"]
let stringRepresentation = array.joinWithSeparator("-") // "1-2-3"

joinWithSeparator is defined as an extension on SequenceType joinWithSeparator被定义为SequenceType的扩展

extension SequenceType where Generator.Element == String {
    /// Interpose the `separator` between elements of `self`, then concatenate
    /// the result.  For example:
    ///
    ///     ["foo", "bar", "baz"].joinWithSeparator("-|-") // "foo-|-bar-|-baz"
    @warn_unused_result
    public func joinWithSeparator(separator: String) -> String
}

#5楼

Mine works on NSMutableArray with componentsJoinedByString 我的工作与组件JoinedByString NSMutableArray

var array = ["1", "2", "3"]
let stringRepresentation = array.componentsJoinedByString("-") // "1-2-3"

#6楼

With Swift 5, according to your needs, you may choose one of the following Playground sample codes in order to solve your problem. 使用Swift 5，您可以根据需要选择以下Playground示例代码之一来解决您的问题。

Turning an array of Character s into a String with no separator: 将Character数组转换为不带分隔符的String ：

let characterArray: [Character] = ["J", "o", "h", "n"]
let string = String(characterArray)

print(string)
// prints "John"

Turning an array of String s into a String with no separator: 将String数组转换为不带分隔符的String ：

let stringArray = ["Bob", "Dan", "Bryan"]
let string = stringArray.joined(separator: "")

print(string) // prints: "BobDanBryan"

Turning an array of String s into a String with a separator between words: 将String数组转换为单词之间带有分隔符的String ：

let stringArray = ["Bob", "Dan", "Bryan"]
let string = stringArray.joined(separator: " ")

print(string) // prints: "Bob Dan Bryan"

Turning an array of String s into a String with a separator between characters: 将String数组转换为在字符之间使用分隔符的String ：

let stringArray = ["car", "bike", "boat"]
let characterArray = stringArray.flatMap { $0 }
let stringArray2 = characterArray.map { String($0) }
let string = stringArray2.joined(separator: ", ")

print(string) // prints: "c, a, r, b, i, k, e, b, o, a, t"

Turning an array of Float s into a String with a separator between numbers: 将Float数组转换为String ，并在数字之间使用分隔符：

let floatArray = [12, 14.6, 35]
let stringArray = floatArray.map { String($0) }
let string = stringArray.joined(separator: "-")

print(string)
// prints "12.0-14.6-35.0"