PHP RegExp:如何在表达式中使用换行符? [英] php RegExp: how to use newline in expression?

问题描述

例如，它起作用:

{<div\s+class=\"article\"><h2(.*)</div>}s

如果我这样做，我什么也没得到:

If I do this way, I get nothing:

{<div\s+class=\"article\">
    <h2(.*)
 </div>}s

我怀疑我应该使用一些修饰符，但是我从这里知道是哪个修饰符:

I suspect that I should use some modifier, but I know which one from here: http://php.net/manual/en/reference.pcre.pattern.modifiers.php

推荐答案

这将是/x修饰符:

x (PCRE_EXTENDED)

x (PCRE_EXTENDED)

如果设置了此修饰符，则模式中的空白数据字符将被完全忽略(除非进行转义或在字符类内部)，并且在字符类外部的未转义的#与下一个换行符(包括首字符)之间的字符也将被忽略.这等效于Perl的/x修饰符，并可以在复杂的模式中包含注释.但是请注意，这仅适用于数据字符.空格字符可能永远不会出现在模式中的特殊字符序列中，例如，在序列中(?(会引入条件子模式.

If this modifier is set, whitespace data characters in the pattern are totally ignored except when escaped or inside a character class, and characters between an unescaped # outside a character class and the next newline character, inclusive, are also ignored. This is equivalent to Perl's /x modifier, and makes it possible to include comments inside complicated patterns. Note, however, that this applies only to data characters. Whitespace characters may never appear within special character sequences in a pattern, for example within the sequence (?( which introduces a conditional subpattern.

它还允许注释模式，这非常有用:

It also allows commenting the pattern, which is extremely useful:

{<div\s+class=\"article\">  # many spaces between the div and the attribute
    <h2(.*)                 # don't really care about closing the tag
 </div>}sx

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