extension String {
    func condenseWhitespace() -> String {
        return self.components(separatedBy: CharacterSet.whitespacesAndNewlines)
            .filter { !$0.isEmpty }
            .joined(separator: " ")
    }
}

let string = "  Lorem   \r  ipsum dolar   sit  amet. "
print(string.condensingWhitespace())
// Lorem ipsum dolar sit amet.

遗产快报

NSCharacterSet使这很容易：

func condenseWhitespace(string: String) -> String {
    let components = string.componentsSeparatedByCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).filter({!isEmpty($0)})
    return join(" ",components)
}

var string = "  Lorem   \r  ipsum dolar   sit  amet. "
println(condenseWhitespace(string))
// Lorem ipsum dolar sit amet.

或者如果您希望将其作为字符串扩展名：

extension String {
    func condenseWhitespace() -> String {
        let components = self.componentsSeparatedByCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).filter({!Swift.isEmpty($0)})
        return " ".join(components)
    }
}

var string = "  Lorem   \r  ipsum dolar   sit  amet. "
println(string.condenseWhitespace())
// Lorem ipsum dolar sit amet.

所有信用到NSHipster post on NSCharacterSet。