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preg_match_all
Perform a global regular expression match
(PHP 4, PHP 5)
int preg_match_all ( string pattern, string subject, array &matches [, int flags [, int offset]] )
Searches subject for all matches to the regular expression given in pattern and puts them in matches in the order specified by flags.
After the first match is found, the subsequent searches are continued on from end of the last match.
Parameters
- pattern
The pattern to search for, as a string.
- subject
The input string.
- matches
Array of all matches in multi-dimensional array ordered according to flags.
- flags
Can be a combination of the following flags (note that it doesn't make sense to use
PREG_PATTERN_ORDERtogether withPREG_SET_ORDER):PREG_PATTERN_ORDEROrders 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.
<?php
preg_match_all("|<[^>]+>(.*)</[^>]+>|U",
"<b>example: </b><div align=left>this is a test</div>",
$out, PREG_PATTERN_ORDER);
echo $out[0][0] . ", " . $out[0][1] . "\n";
echo $out[1][0] . ", " . $out[1][1] . "\n";
?>The above example will output:
<b>example: </b>, <div align=left>this is a test</div>
example: , this is a testSo, $out[0] contains array of strings that matched full pattern, and $out[1] contains array of strings enclosed by tags.
PREG_SET_ORDEROrders 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.
<?php
preg_match_all("|<[^>]+>(.*)</[^>]+>|U",
"<b>example: </b><div align=\"left\">this is a test</div>",
$out, PREG_SET_ORDER);
echo $out[0][0] . ", " . $out[0][1] . "\n";
echo $out[1][0] . ", " . $out[1][1] . "\n";
?>The above example will output:
<b>example: </b>, example:
<div align="left">this is a test</div>, this is a testPREG_OFFSET_CAPTUREIf this flag is passed, for every occurring match the appendant string offset will also be returned. Note that this changes the value of matches in an array where every element is an array consisting of the matched string at offset
0and its string offset into subject at offset1.
If no order flag is given,
PREG_PATTERN_ORDERis assumed.- offset
Normally, the search starts from the beginning of the subject string. The optional parameter offset can be used to specify the alternate place from which to start the search (in bytes).
Note:Using offset is not equivalent to passing
substr($subject, $offset)to preg_match_all() in place of the subject string, because pattern can contain assertions such as ^, $ or (?<=x). See preg_match() for examples.
Return Values
Returns the number of full pattern matches (which might be zero),
or FALSE if an error occurred.
ChangeLog
| Version | Description |
|---|---|
| 4.3.3 | The offset parameter was added |
| 4.3.0 |
The PREG_OFFSET_CAPTURE flag was added
|
Examples
Example 1716. Getting all phone numbers out of some text.
<?php
preg_match_all("/\(? (\d{3})? \)? (?(1) [\-\s] ) \d{3}-\d{4}/x",
"Call 555-1212 or 1-800-555-1212", $phones);
?>
Example 1717. Find matching HTML tags (greedy)
<?php
// The \\2 is an example of backreferencing. This tells pcre that
// it must match the second set of parentheses in the regular expression
// itself, which would be the ([\w]+) in this case. The extra backslash is
// required because the string is in double quotes.
$html = "<b>bold text</b><a href=howdy.html>click me</a>";
preg_match_all("/(<([\w]+)[^>]*>)(.*)(<\/\\2>)/", $html, $matches, PREG_SET_ORDER);
foreach ($matches as $val) {
echo "matched: " . $val[0] . "\n";
echo "part 1: " . $val[1] . "\n";
echo "part 2: " . $val[3] . "\n";
echo "part 3: " . $val[4] . "\n\n";
}
?>The above example will output:
matched: <b>bold text</b>
part 1: <b>
part 2: bold text
part 3: </b>
matched: <a href=howdy.html>click me</a>
part 1: <a href=howdy.html>
part 2: click me
part 3: </a>