How to search in an array with preg_match?
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
Use preg_grep
$array = preg_grep( '/(my\n+string\n+)/i', array( 'file' , 'my string => name', 'this'));
You can use array_walk
to apply your preg_match
function to each element of the array.