Summary of commonly used PHP regular expression functions (code examples)-PHP Tutorial-php.cn

Summary of commonly used PHP regular expression functions (code examples)

不言

Release： 2023-04-03 22:50:01

Original

1555 people have browsed it

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 &#39;mull&#39;;
    }elseif(is_array($val) || is_object($val)){        
    //打印数组或者对象
        echo &#39;<pre class="brush:php;toolbar:false">&#39;;
        print_r($val);        
        echo &#39;

'; }else{ //打印string int float echo $val; } }

Copy after login

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 = &#39;/[0-9]/&#39;;
  $subject=&#39;b5fg4sgf3sd2f1g&#39;;
  $m1 =preg_match($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
        )

)
 */

Copy after login

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 = &#39;/[0-9]/&#39;;
$subject=&#39;b65fg4sgf3sd2f1g&#39;;
$replacement = &#39;_&#39;;
$str1 = preg_replace($pattern,$replacement,$subject);
$str2 = preg_filter($pattern,$replacement,$subject);
echo &#39;<hr>&#39;;
show($str1);
echo &#39;<br>&#39;;
show($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(&#39;/[123]/&#39;,&#39;/[456]/&#39;,&#39;/[789]/&#39;);
 $subject=&#39;b123fg3456sgf3789f1g&#39;;
 $replacement = array(&#39;天&#39;,&#39;地&#39;,&#39;人&#39;);
 $str3 = preg_replace($pattern,$replacement,$subject);
 $str4 = preg_filter($pattern,$replacement,$subject);
 echo &#39;<hr>&#39;;
show($str3);
echo &#39;<br>&#39;;
show($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(&#39;/[123]/&#39;,&#39;/[456]/&#39;,&#39;/[789]/&#39;);
 $subject=array(&#39;b&#39;,&#39;fg3&#39;,&#39;456&#39;,&#39;sgf&#39;,&#39;789&#39;,&#39;fg&#39;);
 $replacement = array(&#39;天&#39;,&#39;地&#39;,&#39;人&#39;);
 $str5 = preg_replace($pattern,$replacement,$subject);
 $str6 = preg_filter($pattern,$replacement,$subject);
 echo &#39;<hr>&#39;;
show($str5);
echo &#39;<br>&#39;;
show($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
)
 */

Copy after login

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 = &#39;/[0-9]/&#39;;
$subject=array(&#39;b&#39;,&#39;fg3&#39;,&#39;456&#39;,&#39;sgf&#39;,&#39;789&#39;,&#39;fg&#39;);
$arr = preg_grep($pattern,$subject);
show($arr);
/*
Array
(
    [1] => fg3
    [2] => 456
    [4] => 789
)
 */

Copy after login

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 = &#39;/[0-9]/&#39;;
$subject=&#39;bfg3456sgf789fg&#39;;
$arr = preg_split($pattern,$subject);
show($arr);
/*
Array
(
    [0] => bfg
    [1] =>
    [2] =>
    [3] =>
    [4] => sgf
    [5] =>
    [6] =>
    [7] => fg
)
 */

Copy after login

5. preg_quote($str) regular operator translation

/*
 * preg_quote($str) 正则运算符转译
 *  . \ + * ? [ ^ ] $ () {} = ! < > | : -
 *
 */
 echo &#39;<hr>&#39;;
 $str = "qewr{asdf}[123]";
 $str =preg_quote($str);
print_r($str);
/*
qewr\{asdf\}\[123\]
*/

Copy after login

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

The above is the detailed content of Summary of commonly used PHP regular expression functions (code examples). For more information, please follow other related articles on the PHP Chinese website!