从不包含空格的字符串中删除空白字符集

Question

如何从字符串中删除空白字符集,但保留字之间的单个空格.我想删除双空格和三重空格等...

Answer 1

斯威夫特3

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

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

遗产斯威夫特

NSCharacterSet 让这很容易:

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.

或者如果您希望它作为String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.

全部归功于NSCharacterSet上的NSHipster帖子.

Answer 2

Swift 2兼容代码:

extension String {
    var removeExcessiveSpaces: String {
        let components = self.componentsSeparatedByCharactersInSet(NSCharacterSet.whitespaceCharacterSet())
        let filtered = components.filter({!$0.isEmpty})
        return filtered.joinWithSeparator(" ")
    }
}

用法:

let str = "test  spaces    too many"
print(str.removeExcessiveSpaces)
// Output: test spaces too many