array_find() - A case insensitive array_search() with partial matches

gistfile1.php

<?php
/**
 * Case in-sensitive array_search() with partial matches
 *
 * @param string $needle   The string to search for.
 * @param array  $haystack The array to search in.
 *
 * @author Bran van der Meer <branmovic@gmail.com>
 * @since 29-01-2010
 */
function array_find($needle, array $haystack)
{
    foreach ($haystack as $key => $value) {
        if (false !== stripos($value, $needle)) {
            return $key;
        }
    }
    return false;
}

If you're not afraid of a little bit of regex, preg_grep() is native PHP and will likely do this more quickly:

https://www.php.net/manual/en/function.preg-grep.php

// Looking for "first " at beginning of any array values

// Get results
$results = array_values( preg_grep( '/^first (\w+)/i', array(
    'f', 'fun', 'first', 'first match', 'not first'
) ) );

// Output
var_dump( $results );

// Results
array (size=1)
  0 => string 'first match' (length=11)

The PREG_GREP_INVERT flag even allows quickly targeting the inverse.

// Looking for inverse of "first " at beginning of any array values

// Get results
$results = array_values( preg_grep( '/^first (\w+)/i', array(
    'f', 'fun', 'first', 'first match', 'not first'
), PREG_GREP_INVERT ) );

// Output
var_dump( $results );

// Results
array (size=4)
  0 => string 'f' (length=1)
  1 => string 'fun' (length=3)
  2 => string 'first' (length=5)
  3 => string 'not first' (length=9)

Note that I'm using /i above to denote case insensitivity.

Very helpful. Thanks.