How to search in an array with preg_match?
PhpRegexArraysPreg MatchPhp Problem Overview
How do I search in an array with preg_match?
Example:
<?php
if( preg_match( '/(my\n+string\n+)/i' , array( 'file' , 'my string => name', 'this') , $match) )
{
//Excelent!!
$items[] = $match[1];
} else {
//Ups! not found!
}
?>
Php Solutions
Solution 1 - Php
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
Solution 2 - Php
Use preg_grep
$array = preg_grep(
'/(my\n+string\n+)/i',
array( 'file' , 'my string => name', 'this')
);
Solution 3 - Php
$haystack = array (
'say hello',
'hello stackoverflow',
'hello world',
'foo bar bas'
);
$matches = preg_grep('/hello/i', $haystack);
print_r($matches);
Output:
Array
(
[1] => say hello
[2] => hello stackoverflow
[3] => hello world
)
Solution 4 - Php
You can use array_walk to apply your preg_match function to each element of the array.
Solution 5 - Php
$items = array();
foreach ($haystacks as $haystack) {
if (preg_match($pattern, $haystack, $matches)
$items[] = $matches[1];
}