preg_match

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Description

int preg_match_all (string pattern, string subject, array matches [, int order])

Searches subject for all matches to the regular expression given in pattern and puts them in matches in the order specified by order.

After the first match is found, the subsequent searches are continued on from end of the last match.

order can be one of two things:

PREG_PATTERN_ORDER

Orders results so that $matches[0] is an array of full pattern matches, $matches[1] is an array of strings matched by the first parenthesized subpattern, and so on.

preg_match_all ("|<[^>]+>(.*)</[^>]+>|U", 
    "<b>example: </b><div align=left>this is a test</div>", 
    $out, PREG_PATTERN_ORDER);
print $out[0][0].", ".$out[0][1]."\n";
print $out[1][0].", ".$out[1][1]."\n"

This example will produce:

<b>example: </b>, <div align=left>this is a test</div>
example: , this is a test

So, $out[0] contains array of strings that matched full pattern, and $out[1] contains array of strings enclosed by tags.

PREG_SET_ORDER

Orders results so that $matches[0] is an array of first set of matches, $matches[1] is an array of second set of matches, and so on.

preg_match_all ("|<[^>]+>(.*)</[^>]+>|U", 
    "<b>example: </b><div align=left>this is a test</div>", 
    $out, PREG_SET_ORDER);
print $out[0][0].", ".$out[0][1]."\n";
print $out[1][0].", ".$out[1][1]."\n"

This example will produce:

<b>example: </b>, example: 
<div align=left>this is a test</div>, this is a test

In this case, $matches[0] is the first set of matches, and $matches[0][0] has text matched by full pattern, $matches[0][1] has text matched by first subpattern and so on. Similarly, $matches[1] is the second set of matches, etc.

If order is not specified, it is assumed to be PREG_PATTERN_ORDER.

Returns the number of full pattern matches, or false if no match is found or an error occurred.

Example 1. Getting all phone numbers out of some text.
preg_match_all ("/$? (\d{3})? $? (?(1) [\-\s] ) \d{3}-\d{4}/x", "Call 555-1212 or 1-800-555-1212", $phones);

Example 2. Find matching HTML tags (greedy)
// the \\2 is an example of backreferencing. This tells pcre that // it must match the 2nd set of parenthesis in the regular expression // itself, which would be the ([\w]+) in this case. $html = "bold text<a href=howdy.html>click me</a> preg_match_all ("/(<([\w]+)[^>]*>)(.*)(<\/\\2>)/", $html, $matches); for ($i=0; $i< count($matches[0]); $i++) { echo "matched: ".$matches[0][$i]."\n"; echo "part 1: ".$matches[1][$i]."\n"; echo "part 2: ".$matches[3][$i]."\n"; echo "part 3: ".$matches[4][$i]."\n\n"; }
This example will produce:
matched: bold text part 1: part 2: bold text part 3: matched: <a href=howdy.html>click me</a> part 1: <a href=howdy.html> part 2: click me part 3: </a>