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Detailed explanation of the use of preg_match function in PHP (with code examples)
- autoloadOriginal
- 2021-04-16 14:25:418281browse
This article introduces the preg_match() function in PHP in more detail, supplemented by examples, so that everyone can take a look. preg_match() function, how to match regular expression.
Syntax:
preg_match ( string $pattern , string $subject ,array &$matches = ? ,int $flags = 0 ,int $offset = 0 )
$pattern: Pattern to search, string type.
$subject: Input string.
$matches: If the parameter matches is provided, it will be populated as search results. $matches[0] will contain the text matched by the complete pattern, $matches[1] will contain the text matched by the first captured subgroup, and so on.
$flags: Can be set to a combination of the following tag values: PREG_UNMATCHED_AS_NULL, PREG_OFFSET_CAPTURE
- ##$offset: Optional parameter offset is used to specify Start searching from a certain position in the target string (unit is bytes).
- Return value: number of matches. Its value will be 0 (no match) or 1 because preg_match() will stop matching after the first match. An error occurred preg_match() returned FALSE.
Usage example:
<?php
//从URL中获取主机名称
preg_match('@^(?:http://)?([^/]+)@i',
"http://www.php.cn/index.html", $matches);
$host = $matches[1];
//获取主机名称的后面两部分
preg_match('/[^.]+\.[^.]+$/', $host, $matches);
echo "admin name is: {$matches[0]}\n";
?>输出：admin name is: php.cn
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