我怎么能在多行分割字符串,如下面?

var text:String = "This is some text
                   over multiple lines"

当前回答

下面是一个代码片段,用n个字符分隔字符串:

//: A UIKit based Playground for presenting user interface

import UIKit
import PlaygroundSupport

class MyViewController : UIViewController {
    override func loadView() {

        let str = String(charsPerLine: 5, "Hello World!")
        print(str) // "Hello\n Worl\nd!\n"

    }
}

extension String {

    init(charsPerLine:Int, _ str:String){

        self = ""
        var idx = 0
        for char in str {
            self += "\(char)"
            idx = idx + 1
            if idx == charsPerLine {
                self += "\n"
                idx = 0
            }
        }

    }
}

其他回答

另一种方法是,如果你想使用带有预定义文本的字符串变量,

var textFieldData:String = "John"
myTextField.text = NSString(format: "Hello User, \n %@",textFieldData) as String
myTextField.numberOfLines = 0

下面的例子描述了一个多行连续,使用圆括号作为一个简单的解决方法,以解决Xcode 6.2 Beta版本的Swift错误,它抱怨表达式太复杂,无法在合理的时间内解析,并考虑将其分解为更小的片段:

    .
    .
    .
    return String(format:"\n" +
                    ("    part1:    %d\n"    +
                     "    part2:    %d\n"    +
                     "    part3:  \"%@\"\n"  +
                     "    part4:  \"%@\"\n"  +
                     "    part5:  \"%@\"\n"  +
                     "    part6:  \"%@\"\n") +
                    ("    part7:  \"%@\"\n"  +
                     "    part8:  \"%@\"\n"  +
                     "    part9:  \"%@\"\n"  +
                     "    part10: \"%@\"\n"  +
                     "    part12: \"%@\"\n") +
                     "    part13:  %f\n"     +
                     "    part14:  %f\n\n",
                    part1, part2, part3, part4, part5, part6, part7, part8, 
                    part9, part10, part11, part12, part13, part14)
    .
    .
    .

Swift 4通过提供多行字符串文字支持解决了这个问题。要开始字符串字面量,添加三个双引号(" " " ")并按回车键,按回车键后开始写带有任何变量的字符串,换行符和双引号,就像你在记事本或任何文本编辑器中写的那样。要结束多行字符串文字再次写入(" " ")在新行。

参见下面的例子

     let multiLineStringLiteral = """
    This is one of the best feature add in Swift 4
    It let’s you write “Double Quotes” without any escaping
    and new lines without need of “\n”
    """

print(multiLineStringLiteral)

下面是一个代码片段,用n个字符分隔字符串:

//: A UIKit based Playground for presenting user interface

import UIKit
import PlaygroundSupport

class MyViewController : UIViewController {
    override func loadView() {

        let str = String(charsPerLine: 5, "Hello World!")
        print(str) // "Hello\n Worl\nd!\n"

    }
}

extension String {

    init(charsPerLine:Int, _ str:String){

        self = ""
        var idx = 0
        for char in str {
            self += "\(char)"
            idx = idx + 1
            if idx == charsPerLine {
                self += "\n"
                idx = 0
            }
        }

    }
}

迅速:

@connor是正确答案,但如果你想在打印语句中添加行,你要寻找的是\n和/或\r,这些被称为转义序列或转义字符,这是一个关于该主题的Apple文档链接。

例子:

print("First line\nSecond Line\rThirdLine...")