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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.
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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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