preg_match

Perform a regular expression match.

preg_match Function synopsis

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

Parameters

$pattern

Typestring

The pattern to search for, as a string.

$subject

Typestring

The input string.

$matches

Passed by reference, OptionalDefault valuenull

If $matches is provided, then it is filled with the results of search. $matches[0] will contain the text that matched the full pattern, $matches[1] will have the text that matched the first captured parenthesized subpattern, and so on.

$flags

OptionalTypeintDefault value0

$flags can be a combination of the following flags:

$flags accepts one or a bitmask of the following constant values:

• PREG_OFFSET_CAPTURE
• PREG_UNMATCHED_AS_NULL

$offset

OptionalTypeintDefault value0

Normally, the search starts from the beginning of the subject string. The optional parameter $offset can be used to specify the alternate place from which to start the search (in bytes).

Note that the parameter $matches is passed by reference, and contains additional/updated context data that may be useful.

Return value

Typeint|false

preg_match returns 1 if the $pattern matches given $subject, 0 if it does not, or false on failure.