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

下面是一个简单的实现(Swift 5.4+),使用resultBuilder来清理语法!

@resultBuilder
public struct StringBuilder {
    public static func buildBlock(_ components: String...) -> String {
        return components.reduce("", +)
    }
}

public extension String {
    init(@StringBuilder _ builder: () -> String) {
        self.init(builder())
    }
}

用法:

String {
    "Hello "
    "world!"
} 
// "Hello world!"

其他回答

Swift 4支持多行字符串字面值。除了换行符,它们还可以包含未转义的引号。

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

旧版本的Swift不允许你在多行上有一个字面值,但你可以在多行上添加字面值:

var text = "This is some text\n"
         + "over multiple lines\n"

一种方法是将标签文本设置为attributedText,并更新字符串变量以包含换行符的HTML (<br />)。

例如:

var text:String = "This is some text<br />over multiple lines"
label.attributedText = text

输出:

This is some text
over multiple lines

希望这能有所帮助!

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)
    .
    .
    .

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