PHP 正则表达式将字母数字字符串与一些(但不是全部)标点符号匹配 [英] PHP regular expression to match alpha-numeric strings with some (but not all) punctuation

问题描述

我在 PHP 中编写了一个正则表达式，以允许包含除 & 或 @ 之外的任何标点符号的字母数字字符串.从本质上讲，除了这两个字符之外，我需要允许标准美式键盘上的任何内容.我花了一段时间才想出以下正则表达式，这似乎正在做我需要的:

I've written a regular expression in PHP to allow strings that are alpha-numeric with any punctuation except & or @. Essentially, I need to allow anything on a standard American keyboard with the exception of those two characters. It took me a while to come up with the following regex, which seems to be doing what I need:

if (ereg("[^]A-Za-z0-9\[!\"#$%'()*+,./:;<=>?^_`{|}~\-]", $test_string)) {
  // error message goes here
}

这让我想到了我的问题……有没有更好、更简单或更有效的方法?

Which brings me to my question... is there a better, simpler, or more efficient way?

推荐答案

看看字符范围:

@[!-%'-?A-~]+@

这将排除字符 &(\0x26) 和 @(0x40).查看 ASCII 表，您可以看到它是如何工作的:感叹号是 ASCII 集中的第一个字符，不是空格.然后它将匹配所有内容，包括 % 字符，它紧跟在 & 符号之前.然后是下一个范围，直到 @ 字符，它位于 ? 和 A 之间.之后，我们将所有内容匹配到标准 ASCII 字符集的末尾，即 ~.

This will exclude the characters & (\0x26) and @ (0x40). Looking at an ASCII Table,you can see how this works: The exclamation mark is the first character in the ASCII set, that is not whitespace. It will then match everything up to and including the % character, which immediately precedes the ampersand. Then the next range until the @ character, which lies between ? and A. After that, we match everything unto the end of the standard ASCII character set which is a ~.

为了使内容更具可读性，您也可以考虑分两步执行此操作:首先，过滤掉默认 ASCII 范围之外的任何内容.

To make things more readable, you might also consider to do this in two steps: At first, filter anything outside of the default ASCII range.

@[!-~]+@

在第二步中，过滤不需要的字符，或者简单地对字符执行 str_pos.

In a second step, filter your undesired characters, or simply do a str_pos on the characters.

最后，您可以将它与您开始的内容进行比较，看看它是否包含任何不需要的字符.

At the end, you can compare it with what you started to see whether it contained any undesired characters.

相反，您也可以在第二步中使用这样的正则表达式./[^@&]+/

Instead, you could also use a regex such as this for the second step. /[^@&]+/

这些步骤是可以互换的，首先在 @ 或 & 上执行 str_pos 作为识别坏字符的第一步，可能会更好地提高性能.

The steps are interchangeable and doing a str_pos on @ or & as a first step, to identify bad characters, may be better performance wise.

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