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Homephp教程php手册正则表达式简介

正则表达式简介

Jun 13, 2016 am 11:21 AM
Canand术语conceptregularIntroductionexpressionthis

1.正则表达式
如果原来没有使用过正则表达式,那么可能对这个术语和概念会不太熟悉。不过,它们并不是您想象的那么新奇。
请回想一下在硬盘上是如何查找文件的。您肯定会使用 ? 和 * 字符来帮助查找您正寻找的文件。? 字符匹配文件名中的
单个字符,而 * 则匹配一个或多个字符。一个如 'data?.dat' 的模式可以找到下述文件:
data1.dat
data2.dat
datax.dat
dataN.dat
如果使用 * 字符代替 ? 字符,则将扩大找到的文件数量。'data*.dat' 可以匹配下述所有文件名:
data.dat
data1.dat
data2.dat
data12.dat
datax.dat
dataXYZ.dat
尽管这种搜索文件的方法肯定很有用,但也十分有限。? 和 * 通配符的有限能力可以使你对正则表达式能做什么有一个概
念,不过正则表达式的功能更强大,也更灵活。


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