如何检查字符串是否包含空格/字母数字/等字符？ [英] How can I check to see if a string contains characters of whitespace/alphanumeric/etc?

问题描述

如何使用Swift中的ctype.h库来使用 isAlpha 或 isSpace 在人物？或者有更好的Swift方式吗？

How can you use the "ctype.h" library in Swift to be able to use isAlpha or isSpace on characters? Or is there a better, Swift, way of doing it?

这个问题已得到解答，但它似乎不起作用：
Swift：如何确定字母是字母数字还是数字

This question is answered, but it doesn't seem to work: Swift: how to find out if letter is Alphanumeric or Digit

它没有指定如何导入库。有人能指出我正确的方向吗？

It doesn't specify how to import the library. Could someone point me in the right direction?

这是我到目前为止所得到的：

Here's what I've got so far:

extension String {
    subscript (i : Int) -> String {
        return String(Array(self)[i])
    }
}

let whitespace = NSCharacterSet.whitespaceCharacterSet()

let phrase = "Test case"

for var i=0; i<countElements(phrase); i++ {
    if whitespace.characterIsMember(phrase[i]) { //error
        println("char is whitespace")
    }
}

推荐答案

对整个字符串使用NSCharacter，而不是逐个字符：

Use NSCharacter on the entire string,not character-by-character:

let whitespace = NSCharacterSet.whitespaceCharacterSet()

let phrase = "Test case"
let range = phrase.rangeOfCharacterFromSet(whitespace)

// range will be nil if no whitespace is found
if let test = range {
    println("whitespace found")
}
else {
    println("whitespace not found")
}

输出：

whitespace found

这篇关于如何检查字符串是否包含空格/字母数字/等字符？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！