正则表达式点是否带方括号 [英] regexp dot with square brackets or not

问题描述

.* 和 [.]* 之间的确切区别是什么?

What is the exact difference between .* and [.]*?

我试图将这些放在括号内，以供反向引用，但看到结果不一样，虽然我不明白为什么.

I have tried to put these inside parentheses, for back-reference, and saw the results are not the same although I don't understand why.

. 应该匹配任何单个字符.

The . is supposed to match any single character.

所以我猜它是否在方括号内对于 * (匹配零个或多个)运算符不应该很重要.但它是.为什么?

So I guess whether it's inside square brackets or not should not be important with the * (match zero or more) operator. But it is. Why?

推荐答案

在 .* 中，点是匹配除换行符以外的任何字符的特殊字符(如果指定DOTALL 修饰符).在字符类 ([.]) 中，点失去其特殊含义并开始匹配文字点.

In .*, a dot is a special character matching any character but a newline (it will match all characters if you specify a DOTALL modifier). In a character class ([.]), a dot loses its special meaning and starts matching a literal dot.

这是所有正则表达式风格的通用行为.

It is a universal behavior across all regex flavors.

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