php - 解释这个正则表达式

Question

我是正则表达式的新手，谁能帮我弄清楚这行说的是什么：

$body = preg_replace('/\s{6,}/ms','',$body);

提前致谢。

Answer 1

$body = preg_replace('/\s{6,}/ms','',$body);

Replace space (\s), which occurs 6 to undefined times ({6,}) with nothing. Do this multiline. (/m). The s could be removed, it adds no value when you don't use the "all characters" character (.).

Answer 2

它删除了至少 6 个连续的空白字符的出现。

\s - 空白

定义为（水平）制表符、空格、换行、回车或换页。

模式修饰符是无用的顺便说一句：

• m改变和的^行为$
• s也.匹配换行符；否则它将停在一行的末尾。

Answer 3

基本上它的说法是用连续六个空格替换任何东西。

\s  = space
{6,} = between 6 and (since the second number after the comman is blank) 6
\ms = Used together, as /ms, they let the "." match any character whatsoever, while still allowing "^" and "$" to match, respectively, just after and just before newlines within the string.

还可以看看perldoc 中的 perl 正则表达式，将来可能会有所帮助。