preg_match Perform a regular expression match &reftitle.description; intpreg_match stringpattern stringsubject arraymatches intflags0 intoffset0 Searches subject for a match to the regular expression given in pattern. &reftitle.parameters; pattern The pattern to search for, as a string. subject The input string. matches If matches is provided, then it is filled with the results of search. $matches[0] will contain the text that matched the full pattern, $matches[1] will have the text that matched the first captured parenthesized subpattern, and so on. flags flags can be a combination of the following flags: PREG_OFFSET_CAPTURE If this flag is passed, for every occurring match the appendant string offset (in bytes) will also be returned. Note that this changes the value of matches into an array where every element is an array consisting of the matched string at offset 0 and its string offset into subject at offset 1. ]]> &example.outputs; Array ( [0] => foobarbaz [1] => 0 ) [1] => Array ( [0] => foo [1] => 0 ) [2] => Array ( [0] => bar [1] => 3 ) [3] => Array ( [0] => baz [1] => 6 ) ) ]]> PREG_UNMATCHED_AS_NULL If this flag is passed, unmatched subpatterns are reported as &null;; otherwise they are reported as an empty string. ]]> &example.outputs; string(2) "ac" [1]=> string(1) "a" [2]=> string(0) "" [3]=> string(1) "c" } array(4) { [0]=> string(2) "ac" [1]=> string(1) "a" [2]=> NULL [3]=> string(1) "c" } ]]> offset Normally, the search starts from the beginning of the subject string. The optional parameter offset can be used to specify the alternate place from which to start the search (in bytes). Using offset is not equivalent to passing substr($subject, $offset) to preg_match in place of the subject string, because pattern can contain assertions such as ^, $ or (?<=x). Compare: ]]> &example.outputs; while this example ]]> will produce Array ( [0] => def [1] => 0 ) ) ]]> Alternatively, to avoid using substr, use the \G assertion rather than the ^ anchor, or the A modifier instead, both of which work with the offset parameter. &reftitle.returnvalues; preg_match returns 1 if the pattern matches given subject, 0 if it does not, or &false; if an error occurred. &return.falseproblem; &reftitle.changelog; &Version; &Description; 7.2.0 The PREG_UNMATCHED_AS_NULL is now supported for the $flags parameter. &reftitle.examples; ]]> ]]> ]]> &example.outputs; \w+): (?P\d+)/', $str, $matches); /* This also works in PHP 5.2.2 (PCRE 7.0) and later, however * the above form is recommended for backwards compatibility */ // preg_match('/(?\w+): (?\d+)/', $str, $matches); print_r($matches); ?> ]]> &example.outputs; foobar: 2008 [name] => foobar [1] => foobar [digit] => 2008 [2] => 2008 ) ]]> &reftitle.notes; Do not use preg_match if you only want to check if one string is contained in another string. Use strpos instead as it will be faster. &reftitle.seealso; PCRE Patterns preg_quote preg_match_all preg_replace preg_split preg_last_error preg_last_error_msg