Regex

PHP String Function: Regex
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preg_match()

preg_match(string $pattern, string $subject, array &$matches = null, int $flags = 0, int $offset = 0): int|false

Perform a regular expression match

preg_match('/(foo)(bar)(baz)/', 'foobarbaz', $matches, PREG_OFFSET_CAPTURE);
print_r($matches);
// Array
// (
//     [0] => Array
//         (
//             [0] => foobarbaz
//             [1] => 0
//         )
//     [1] => Array
//         (
//             [0] => foo
//             [1] => 0
//         )
//     [2] => Array
//         (
//             [0] => bar
//             [1] => 3
//         )
//     [3] => Array
//         (
//             [0] => baz
//             [1] => 6
//         )

// )

preg_match_all()

preg_match_all(string $pattern, string $subject, array &$matches = null, int $flags = 0, int $offset = 0): int|false

preg_match_all(
    '/(?J)(?<match>foo)|(?<match>bar)/',
    'foo bar',
    $matches,
    PREG_PATTERN_ORDER
);
print_r($matches['match']);
// Array
// (
//     [0] => 
//     [1] => bar
// )

preg_replace()

preg_replace(string|array $pattern, string|array $replacement, string|array $subject, int $limit = -1, int &$count = null): string|array|null

Perform a regular expression search and replace

$string = 'April 15, 2003';
$pattern = '/(\w+) (\d+), (\d+)/i';
$replacement = '${1}1,$3';
echo preg_replace($pattern, $replacement, $string);
// April1,2003

preg_split()

preg_split(string $pattern, string $subject, int $limit = -1, int $flags = 0): array|false

Split string by a regular expression

$keywords = preg_split("/[\s,]+/", "hypertext language, programming");
print_r($keywords);
// Array
// (
//     [0] => hypertext
//     [1] => language
//     [2] => programming
// )

preg_quote()

preg_quote(string $str, ?string $delimiter = null): string

Quote regular expression characters

$keywords = '$40 for a g3/400';
$keywords = preg_quote($keywords, '/');
echo $keywords; // returns \$40 for a g3\/400