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HomeBackend DevelopmentPHP TutorialPHP regular expressions - application of greedy mode (or +) and lazy mode (? or +?)

.表示除\n之外的任意字符; *表示匹配0-无穷; +表示匹配1-无穷;.* — 表示匹配0个或多个处换行符以外的字符;.+ — 表示匹配1个或多个处换行符以外的字符;后边没有?时表示贪婪模式(非懒惰模式);后边多一个?表示懒惰模式;?必须跟在*或者+后边用; 如:PHP regular expressions - application of greedy mode (or +) and lazy mode (? or +?) 如果用正则匹配src中内容非懒惰模式匹配 src=".*" 匹配结果是:src="test.jpg" width="60" height="80" 意思是从="往后匹配,直到最后一个"匹配结束 懒惰模式正则: src=".*?" 结果:src="test.jpg" 因为匹配到第一个"就结束了一次匹配。不会继续向后匹配。在懒惰模式的正则(.*?或.+?)应用中会出现一种特殊的情况,如:}> 我是测试数据如果使用懒惰模式的正则匹配里面的内容(当的内侧都存在空格,并且这个空格可有可无时),我们一般这样写正则:'/\s*\}>(.+?)/ies' 特别注意其中有颜色的部分,尤其是绿色的部分。当懒惰正则后面紧跟着一个用*修饰的原子时,如果在}>前面存在“可用绿色部分(贪婪)匹配的内容”时,它会以绿色部分匹配到的内容为懒惰模式的匹配结束点,匹配到这里后就结束匹配。如果在}>前面不存在“可用绿色部分(贪婪)匹配的内容”时,它会以绿色部分后面紧跟的一个原子(黄色部分)
为懒惰模式的匹配结束点,匹配到这里后就结束匹配。关于“贪婪模式”和“懒惰模式”,可参考博文“php正则表达式—修正模式”

The above introduces the application of PHP regular expressions - greedy mode (or +) and lazy mode (? or +?), including the relevant content. I hope it will be helpful to friends who are interested in PHP tutorials.

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