function ($e) use ($query, $field) { return strpos($e[$field], $query) >= 0; } code example

Example 1: find in php string or

$a = 'How are you?';

if (strpos($a, 'are') !== false) {
    echo 'true';
}

Example 2: strpos

strpos ( string $haystack , mixed $needle [, int $offset = 0 ] ) : int