Question

For example:

main array is: array(0 => 'A', 1 => 'A', 2 => 'B', 3 => 'B', 4 => 'B');

pattern is: array('A', 'B');

expected answer: array( array(0, 2), array(1, 3) )

one more example:

main array array(0 => 'F', 5 => 'G', 78 => 'R', 2 => 'D');

pattern array('G', 'R', 'F');

expected answer: array(array(5, 78, 0))

How can I find all occurrences of pattern in array?

Answer 1

Here’s an function that uses recursion.

function array_pattern($array, $pattern){
    $ret = array(array());
    $found = true;
    foreach($pattern as $val){
        $x = array_search($val, $array);
        if($x === FALSE){
            $found = FALSE;
            break;
        }
        unset($array[$x]);
        $ret[0][] = $x;
    }
    return $found ? array_merge($ret, array_pattern($array, $pattern)) : array();
}

Call it like this:

$a = array_pattern(array(0 => 'A', 1 => 'A', 2 => 'B', 3 => 'B', 4 => 'B'), array('A', 'B'));
$b = array_pattern(array(0 => 'F', 5 => 'G', 78 => 'R', 2 => 'D'), array('G', 'R', 'F'));

DEMO: http://codepad.org/JCdsAMGk