检查字符串无效字符？最聪明的办法吗？ [英] Check string for invalid characters? Smartest way?

问题描述

我要检查一些字符串无效字符。随着无效字符，我的意思是不应该存在的字符。什么字符是这些？这是不同的，但我认为那不是说importan，重要的是我应该怎么做的，什么是最简单，最好的方式（性能）来做到这一点？

I would like to check some string for invalid characters. With invalid characters I mean characters that should not be there. What characters are these? This is different, but I think thats not that importan, important is how should I do that and what is the easiest and best way (performance) to do that?

让说，我只想字符串，其中包含的'A-Z'，'空'，''，'$'，'0-9'

Let say I just want strings that contains 'A-Z', 'empty', '.', '$', '0-9'

所以，如果我有这样一个字符串 HELLO计算器的=>无效，因为的'一'，。 好了现在该怎么办呢？我可以做一个名单，其中，焦炭＆GT; ，放在它的每一个字符是不允许的，并检查字符串列表。也许不是一个好主意，因为有很多字符的话。但我可以做一个包含所有允许的字符的右侧列表？接着？对于字符串中的每个字符我比较名单，其中，焦炭＆GT; ？任何智能code这个？而另一个问题：如果我想补充AZ到名单，其中，焦炭＆GT; 我必须手动添加25个字符，但这些字符是因为我在ASCII表知道65-90 ，我可以添加它们更容易？有什么建议么？谢谢

So if i have a string like "HELLO STaCKOVERFLOW" => invalid, because of the 'a'. Ok now how to do that? I could make a List<char> and put every char in it that is not allowed and check the string with this list. Maybe not a good idea, because there a lot of chars then. But I could make a list that contains all of the allowed chars right? And then? For every char in the string I have to compare the List<char>? Any smart code for this? And another question: if I would add A-Z to the List<char> I have to add 25 chars manually, but these chars are as I know 65-90 in the ASCII Table, can I add them easier? Any suggestions? Thank you

推荐答案

您可以使用常规的前pression此：

You can use a regular expression for this:

Regex r = new Regex("[^A-Z0-9.$ ]$");
if (r.IsMatch(SomeString)) {
    // validation failed
}

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从 AZ创建人物列表或 0-9 你可以使用一个简单的循环：

---

To create a list of characters from A-Z or 0-9 you would use a simple loop:

for (char c = 'A'; c <= 'Z'; c++) {
    // c or c.ToString() depending on what you need
}

但你并不需要一个与正则表达式 - pretty的每得多正则表达式引擎理解的范围语法（ AZ ）

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