


What this article brings to you is a summary (code examples) of commonly used functions of PHP regular expressions. It has certain reference value. Friends in need can refer to it. I hope it will be helpful to you.
Commonly used regular expression functions in php
* preg_match()
* preg_match_all()
* preg_replace()
* preg_filter()
* preg_grep()
* preg_split()
* preg_quote()
Next comparison explanation:
Under explanation $pattern usually regular expression $subject usually represents target processing data
Define a method to facilitate viewing the data type:
function show($val = null){ if(empty($val)){ //打印空 echo 'mull'; }elseif(is_array($val) || is_object($val)){ //打印数组或者对象 echo '<pre class="brush:php;toolbar:false">'; print_r($val); echo ''; }else{ //打印string int float echo $val; } }
preg_match() and preg_match_all()
/*方法简单说明*/ preg_match($pattern,$subject,[array &$matches]) //匹配一次 第三个参数可选 匹配结果放置matches数组 preg_match_all($pattern,$subject,array &matches) //匹配多次 三参必选 匹配结果放置matches数组 $pattern = '/[0-9]/'; $subject='b5fg4sgf3sd2f1g'; $m1 =preg_match($pattern,$subject,$arr1); show($m1); show($arr1); /* 1 Array ( [0] => 5 ) */ $m2 =preg_match_all($pattern,$subject,$arr2); show($m2); show($arr2); /* 5 Array ( [0] => Array ( [0] => 5 [1] => 4 [2] => 3 [3] => 2 [4] => 1 ) ) */
2.preg_replace() and preg_filter()
/*方法简单说明*/ /* * * preg_replace与preg_filter * preg_replace($pattern,$replacement,$subject) * //正则替换函数被替换对象是数组 返回全部 //正则替换函数 被替换对象是数组 仅返回被替换元素 * 联想:str_repalce() * echo str_replace("world","Shanghai","Hello world!"); * //得到Hello Shanghai! //第一测 字符串中替换字符串 结论:此处preg_replace()与preg_filter()无区别 $pattern = '/[0-9]/'; $subject='b65fg4sgf3sd2f1g'; $replacement = '_'; $str1 = preg_replace($pattern,$replacement,$subject); $str2 = preg_filter($pattern,$replacement,$subject); echo '<hr>'; show($str1); echo '<br>'; show($str2); /* b__fg_sgf_sd_f_g b__fg_sgf_sd_f_g */ //第二测 字符串中根据数组正则 替换 结论:此处preg_replace()与preg_filter()无区别 $pattern = array('/[123]/','/[456]/','/[789]/'); $subject='b123fg3456sgf3789f1g'; $replacement = array('天','地','人'); $str3 = preg_replace($pattern,$replacement,$subject); $str4 = preg_filter($pattern,$replacement,$subject); echo '<hr>'; show($str3); echo '<br>'; show($str4); /* b天天天fg天地地地sgf天人人人f天g b天天天fg天地地地sgf天人人人f天g */ //第三测 数组中根据数组正则 替换 结论:此处展示preg_repalce()与preg_filter()区别 $pattern = array('/[123]/','/[456]/','/[789]/'); $subject=array('b','fg3','456','sgf','789','fg'); $replacement = array('天','地','人'); $str5 = preg_replace($pattern,$replacement,$subject); $str6 = preg_filter($pattern,$replacement,$subject); echo '<hr>'; show($str5); echo '<br>'; show($str6); /* Array ( [0] => b [1] => fg天 [2] => 地地地 [3] => sgf [4] => 人人人 [5] => fg ) Array ( [1] => fg天 [2] => 地地地 [4] => 人人人 ) */
3 . preg_grep($pattern, array $subject) //Here $subject can only be a one-dimensional array
/*函数说明*/ preg_grep($pattern,array $input)//只可以匹配一维数组 返回匹配成功的数组元素 可以理解preg_grep()为阉割版 preg_filter() 只做了匹配 不作替换 $pattern = '/[0-9]/'; $subject=array('b','fg3','456','sgf','789','fg'); $arr = preg_grep($pattern,$subject); show($arr); /* Array ( [1] => fg3 [2] => 456 [4] => 789 ) */
4 . preg_split($pattern,$subject)//One Successful matching cuts the string into an array for the cutting point
You can understand the upgraded version of explode() of preg_split()
$pattern = '/[0-9]/'; $subject='bfg3456sgf789fg'; $arr = preg_split($pattern,$subject); show($arr); /* Array ( [0] => bfg [1] => [2] => [3] => [4] => sgf [5] => [6] => [7] => fg ) */
5. preg_quote($str) regular operator translation
/* * preg_quote($str) 正则运算符转译 * . \ + * ? [ ^ ] $ () {} = ! < > | : - * */ echo '<hr>'; $str = "qewr{asdf}[123]"; $str =preg_quote($str); print_r($str); /* qewr\{asdf\}\[123\] */
Simple Summary:
Preg_ starts with
Except for the preg_quote function, the first parameter is a regular expression
preg_match form verification, etc.
preg_replace illegal word filtering, etc.
Related recommendations:
PHP regular expression common functions, php regular expression functions
Summary of commonly used PHP regular expressions, php regular expressions_PHP tutorial
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