Simple analysis of common regular expression function in PHP

1. Preg_match () function
The Preg_match () function searches for a pattern in a string, returns True if it exists, otherwise returns false

$pattern = '/php/';
$str = ' php100.com ';
Echo Preg_match ($pattern, $STR);

Output results: 1

2. Preg_grep () function
The Preg_grep () function searches all elements in an array, returning an array of all the elements that match a pattern

$pattern = '/p$/';
$strArray =array (' asp ', ' php ', ' jsp ', ' Python ', ' Ruby ');
Print_r (Preg_grep ($pattern, $strArray));

Output Result:
Array
(
[0] + = ASP
[1] + = PHP
[2] + = JSP
)

3. Preg_match_all () function
The Preg_match_all () function matches all occurrences of the pattern in the string, and then puts all matches into the array

$pattern = '/php[1-5]/';
$str = ' PHP1PHP2PHP3PHP4PHP5PHP6PHP7PHP8 ';
Preg_match_all ($pattern, $str, $out);
Print_r ($out);

Output Result:
Array
(
[0] = = Array
(
[0] = Php1
[1] = PhP2
[2] = PhP3
[3] = PhP4
[4] = PHP5
)

)

4. Preg_quote () function
The Preg_quote () function inserts a backslash in each word match either that has a special meaning for the regular expression syntax.

echo preg_quote (' Apple Price is: $5/kg ');

Output: Apple Price is: \$5/kg

5. Preg_replace () function
The Preg_replace () function searches for all matches and then replaces them with the desired string to return

$pattern = '/php[1-5]/';
$str = ' PHP1PHP2PHP3PHP4PHP5PHP6PHP7PHP8 ';

Echo preg_replace ($pattern, ' PHP ', $str);

Output Result: PHPPHPPHPPHPPHPPHP6PHP7PHP8

6. Preg_split () function
The Preg_split () function splits the string in a case-insensitive manner, forming an array of the resulting string and returning

$pattern = '/[\[email protected]]/';
$STR = ' [email protected] ';

Print_r (Preg_split ($pattern, $str));

Output Result:
Array
(
[0] = Feng
[1] = Yingyuan
[2] = Sina
[3] = = com
[4] = cn
)

Simple analysis of common regular expression function in PHP