正则表达式与preg函数

2016-06-27 / zhangxuefeng

原文链接

operator	DESCRIPTION
^	The circumflex symbol marks the beginning of a pattern, although in some cases it can be omitted
$	Same as with the circumflex symbol, the dollar sign marks the end of a search pattern
.	The period matches any single character
?	It will match the preceding pattern zero or one times
+	It will match the preceding pattern one or more times
*	It will match the preceding pattern zero or more times
|	Boolean OR
–	Matches a range of elements
()	Groups a different pattern elements together
[]	Matches any single character between the square brackets
{min, max}	It is used to match exact character counts
\d	Matches any single digit
\D	Matches any single non digit caharcter
\w	Matches any alpha numeric character including underscore (_)
\W	Matches any non alpha numeric character excluding the underscore character
\s	Matches whitespace character

EXAMPLE	DESCRIPTION
‘/hello/’	It will match the word hello
‘/^hello/’	It will match hello at the start of a string. Possible matches are hello or helloworld, but not worldhello
‘/hello$/’	It will match hello at the end of a string.
‘/he.o/’	It will match any character between he and o. Possible matches are helo or heyo, but not hello
‘/he?llo/’	It will match either llo or hello
‘/hello+/’	It will match hello on or more time. E.g. hello or hellohello
‘/he*llo/’	Matches llo, hello or hehello, but not hellooo
‘/hello	world/’	It will either match the word hello or world
‘/(A-Z)/’	Using it with the hyphen character, this pattern will match every uppercase character from A to Z. E.g. A, B, C…
‘/[abc]/’	It will match any single character a, b or c
‘/abc{1}/’	Matches precisely one c character after the characters ab. E.g. matches abc, but not abcc
‘/abc{1,}/’	Matches one or more c character after the characters ab. E.g. matches abc or abcc
‘/abc{2,4}/’	Matches between two and four c character after the characters ab. E.g. matches abcc, abccc or abcccc, but not abc

常用函数

1. preg_match

2. preg_repalce

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