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

• PHP: preg_grep - Manual

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

• PHP: array_reduce - Manual
• PHP: preg_match - Manual

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

• PHP: preg_match - Manual

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.

http://us3.php.net/array_walk