正则表达式不以点开头或以点结尾 [英] Regex not start with dot or end with dot

问题描述

我需要一个不以点开头或以[-_.]结尾的正则表达式.

I need a regular expression that does not start with a dot or end with [-_.].

这个正则表达式有效，但在第一个条件下失败；它不以点开头:

This regex works but fails for the first condition; it does not start with dot:

^[A-Za-z0-9][^.]*[^-_.][A-Za-z0-9]$

例如:test.com 应该是一个有效的字符串，但它失败了.

For example: test.com should be a valid string but it fails.

推荐答案

从您的上一个问题，您应该能够使用:

From your previous question, you should be able to use:

^[^.].*[^-_.]$

但是如果您希望能够匹配 1 个字符的字符串，您将需要负前瞻:

But if you want to be able to match a 1 character string, you will need negative lookaheads:

^(?![.])(?!.*[-_.]$).+

如果您也想匹配空字符串，只需使用 * 而不是 +.

And if you want to match empty strings too, simply use * instead of +.

^(?![.])(?!.*[-_.]$).*

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