How do I search in an array with preg_match?
Example:
<?php if( preg_match( '/(myn+stringn+)/i' , array( 'file' , 'my string => name', 'this') , $match) ) { //Excelent!! $items[] = $match[1]; } else { //Ups! not found! } ?>
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Answer
In this post I’ll provide you with three different methods of doing what you ask for. I actually recommend using the last snippet, since it’s easiest to comprehend as well as being quite neat in code.
How do I see what elements in an array that matches my regular expression?
There is a function dedicated for just this purpose, preg_grep
. It will take a regular expression as first parameter, and an array as the second.
See the below example:
$haystack = array ( 'say hello', 'hello stackoverflow', 'hello world', 'foo bar bas' ); $matches = preg_grep ('/^hello (w+)/i', $haystack); print_r ($matches);
output
Array ( [1] => hello stackoverflow [2] => hello world )
Documentation
But I just want to get the value of the specified groups. How?
array_reduce
with preg_match
can solve this issue in clean manner; see the snippet below.
$haystack = array ( 'say hello', 'hello stackoverflow', 'hello world', 'foo bar bas' ); function _matcher ($m, $str) { if (preg_match ('/^hello (w+)/i', $str, $matches)) $m[] = $matches[1]; return $m; } // N O T E : // ------------------------------------------------------------------------------ // you could specify '_matcher' as an anonymous function directly to // array_reduce though that kind of decreases readability and is therefore // not recommended, but it is possible. $matches = array_reduce ($haystack, '_matcher', array ()); print_r ($matches);
output
Array ( [0] => stackoverflow [1] => world )
Documentation
Using array_reduce
seems tedious, isn’t there another way?
Yes, and this one is actually cleaner though it doesn’t involve using any pre-existing array_*
or preg_*
function.
Wrap it in a function if you are going to use this method more than once.
$matches = array (); foreach ($haystack as $str) if (preg_match ('/^hello (w+)/i', $str, $m)) $matches[] = $m[1];
Documentation