正则表达式只允许 1 个字符 [英] Regex allows only 1 character

问题描述

$rex = '/^[^<,"@?=>|;#]$/i';

这个正则表达式有问题.这个想法是检查输入字段中的某些字符，如果存在，则抛出错误.

I'm having trouble with this regular expression. The idea is that the input fields are checked for certain characters and if present, throw an error.

这个正则表达式会为每个长度超过 1 个字符的字符串抛出错误.谁能告诉我我做错了什么?

This regex is throwing errors for every string longer than 1 character. Can anyone tell me what I'm doing wrong?

人们说他们看不到我想用这个正则表达式做什么.如果以下字符之一是输入字符串的一部分，我想要做的是拒绝输入:

People are saying they don't see what I want to do with this regex. What I want to do is refuse the input if one of the following characters is part of the entered string:

<> , " @ ? = | ; #

< > , " @ ? = | ; #

JG 的有效"正则表达式可以解决问题.

JG's "valid" regex does the trick.

推荐答案

你在表达式后面有 $ ，在开头有 ^ ，这意味着你正在接受正好一个字符.

You have the $ after your expression and the ^ in the beginning, which means you are accepting exactly one character.

编辑(基于评论):

您可以尝试查看您的输入字段是否仅具有有效字符，通过将其与此匹配(如果匹配，则表示没有无效字符):

You can try to see if your input fields only have valid characters, by matching it against this (if it matches, it means there are no invalid characters):

$rex = '/^[^<,"@$?=>|;#]+$/i'

你也可以反过来，即测试你的输入字段是否有任何无效字符，使用chaos提供的正则表达式:

You can also do the reverse, that is, test if your input fields have any invalid characters, using the regex provided by chaos:

$rex = '/[<,"@$?=>|;#]/';

这样，如果正则表达式匹配，则意味着您有无效字符.

This way, if the regex matches, then it means you have invalid characters.

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