PHP regular expression suffix_PHP tutorial

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Release: 2016-07-13 17:51:50
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Perl-style regular expressions allow single-character options (flags) to be placed after the regular expression pattern to modify the interpretation or behavior of the match. For example, to do a case-insensitive match, you can simply use the i flag:
preg_match('/cat/i', 'Stop, Catherine!'); // returns true returns true
Table 4-12 shows the modifiers from Perl supported in Perl-compatible regular expressions:
Table 4-12: Perl flags

修饰符 意 义
/regexp/i 不区分大小写的匹配
/regexp/s 使句点(.)匹配任何字符,包括换行符(n)
/regexp/x 从模式中删除空白符和注释
/regexp/m 使^匹配换行符 (n)之后的内容,美元符号($)匹配换行符 (n)之前的内容
/regexp/e 如果替换字符串是PHP代码,使用eval()执行该代码来得到实际的替换字符串。
PHP's Perl-compatible regular expression functions also support other modifiers not supported in Perl, as shown in Table 4-13:
Table 4-13: Other PHP flags
修饰符 意 义
/regexp/U 颠倒子模式的贪婪性;*和+尽可能少地匹配而不是尽可能多。
/regexp/u 把模式字符串当作UTF-8编码对待
/regexp/X 如果一个反斜杠之后跟着没有特殊意义的字符,将产生一个错误
/regexp/A 把锚定位在字符串的开头就像模式中有^一样
/regexp/D 使$字符仅匹配一行的末尾
/regexp/S 使表达式解析器更加小心地检查模式的结构,使得第二次运行时(如在一个循环中)加快速度

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