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"

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"

样本

var yourString = "first line \n second line \n third line"

以防您发现+运算符不合适

我写了一个小扩展。

extension String {

    init(swiftLintMultiline strings: String...) {
        self = strings.reduce("", +)
    }
}

你可以这样使用它:

String(swiftLintMultiline:
    "Lorem ipsum dolor sit amet, consectetur adipiscing",
    "elit. Ut vulputate ultrices volutpat. Vivamus eget",
    "nunc maximus, tempus neque vel, suscipit velit.",
    "Quisque quam quam, malesuada et accumsan sodales,",
    "rutrum non odio. Praesent a est porta, hendrerit",
    "lectus scelerisque, pharetra magna. Proin id nulla",
    "pharetra, lobortis ipsum sit amet, vehicula elit. Nulla",
    "dapibus ipsum ipsum, sit amet congue arcu efficitur ac. Nunc imperdi"
)

我在String上使用了一个扩展来实现多行字符串，同时避免编译器挂起的错误。它还允许您指定分隔符，以便您可以像使用Python的join函数一样使用它

extension String {
    init(sep:String, _ lines:String...){
        self = ""
        for (idx, item) in lines.enumerated() {
            self += "\(item)"
            if idx < lines.count-1 {
                self += sep
            }
        }
    }

    init(_ lines:String...){
        self = ""
        for (idx, item) in lines.enumerated() {
            self += "\(item)"
            if idx < lines.count-1 {
                self += "\n"
            }
        }
    }
}



print(
    String(
        "Hello",
        "World!"
    )
)
"Hello
World!"

print(
    String(sep:", ",
        "Hello",
        "World!"
    )
)
"Hello, World!"

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