用户名的正则表达式，允许数字、字母和空格 [英] Regex for username that allows numbers, letters and spaces

问题描述

我正在寻找一些可用于检查有效用户名的正则表达式代码.

I'm looking for some regex code that I can use to check for a valid username.

我希望用户名包含字母(大写和小写)、数字、空格、下划线、破折号和点，但用户名必须以字母或数字开头和结尾.

I would like for the username to have letters (both upper case and lower case), numbers, spaces, underscores, dashes and dots, but the username must start and end with either a letter or number.

理想情况下，也不允许上面列出的任何特殊字符连续重复多次，即它们可以有任意数量的空格/点/破折号/下划线，但必须至少有它们之间有一个数字或字母.

Ideally, it should also not allow for any of the special characters listed above to be repeated more than once in succession, i.e. they can have as many spaces/dots/dashes/underscores as they want, but there must be at least one number or letter between them.

我也很想知道您是否认为这是一个很好的用户名系统?我已经寻找了一些可以做到这一点的正则表达式，但它们似乎都不允许空格，我希望用户名中有一些空格.

I'm also interested to find out if you think this is a good system for a username? I've had a look for some regex that could do this, but none of them seem to allow spaces, and I would like for the usernames to have some spaces in them.

谢谢:)

推荐答案

所以看起来你希望你的用户名有一个单词"部分(字母或数字的序列)，中间穿插一些分隔符"部分.

So it looks like you want your username to have a "word" part (sequence of letters or numbers), interspersed with some "separator" part.

>

正则表达式看起来像这样:

The regex will look something like this:

^[a-z0-9]+(?:[ _.-][a-z0-9]+)*$

这是一个分解示意图:

           _____sep-word…____
          /                  \
^[a-z0-9]+(?:[ _.-][a-z0-9]+)*$             i.e. "word ( sep word )*"
|\_______/   \____/\_______/  |
| "word"     "sep"   "word"   |
|                             |
from beginning of string...   till the end of string

所以本质上我们想要匹配诸如word、word-sep-word、word-sep-word-sep-word、等

So essentially we want to match things like word, word-sep-word, word-sep-word-sep-word, etc.

• 不会有连续的sep中间没有word
• 第一个和最后一个字符将始终是 word 的一部分(即不是 sep 字符)

• There will be no consecutive sep without a word in between
• The first and last char will always be part of a word (i.e. not a sep char)

请注意，对于 [ _.-]，- 位于最后，因此它不是范围定义元字符.(?:...) 是所谓的非捕获组.我们需要括号来对重复进行分组(即(…)*)，但由于我们不需要捕获，我们可以使用(?:…)*相反.

Note that for [ _.-], - is last so that it's not a range definition metacharacter. The (?:…) is what is called a non-capturing group. We need the brackets for grouping for the repetition (i.e. (…)*), but since we don't need the capture, we can use (?:…)* instead.

要允许大写/各种 Unicode 字母等，只需扩展字符类/根据需要使用更多标志.

To allow uppercase/various Unicode letters etc, just expand the character class/use more flags as necessary.

• regular-expressions.info/Anchors、字符类，重复、分组

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