Tri-mensional array looping - php

Question

I'm really stuck at a certain point in my project. I'm trying to convert a two-dimensional array into a three-dimensional array. Currently I´m at this point:
array (size=4)
0 =>
array (size=4)
0 => string 'foo' (length=3)
1 => string 'a' (length=0)
2 => string 'b' (length=0)
3 => string '0' (length=1)
1 =>
array (size=4)
0 => string 'bar' (length=3)
1 => string 'a' (length=0)
2 => string 'b' (length=0)
3 => string '1' (length=1)
2 =>
array (size=4)
0 => string 'bas' (length=3)
1 => string 'a' (length=0)
2 => string 'b' (length=0)
3 => string '1' (length=1)
3 =>
array (size=4)
0 => string 'tas' (length=3)
1 => string 'a' (length=0)
2 => string 'b' (length=0)
3 => string '0' (length=1)
What I would like to do is make a new array with key values of array[ ][3] (I hope this makes any sense) so something like this:
array (size=2)
0 => array (size=2)
0 => array (size=2)
0 => string 'foo' (length=3)
1 => string 'a' (length=0)
2 => string 'b' (length=0)
1 => array (size=2)
0 => string 'tas' (length=3)
1 => string 'a' (length=0)
2 => string 'b' (length=0)
1 => array (size=2)
0 => array (size=2)
0 => string 'bar' (length=3)
1 => string 'a' (length=0)
2 => string 'b' (length=0)
1 => array (size=2)
0 => string 'bas' (length=3)
1 => string 'a' (length=0)
2 => string 'b' (length=0)
Right now this is the best way I can explain it, I'm not sure if I make any sense or if this is even possible, but if anyone could shed a light on this it would be much appreciated!
Thanks in advance,
Thomas

Answer 1

$array = array();
$array[] = array('foo','foo','foo',1);
$array[] = array('a','a','a',1);
$array[] = array('b','a','a',0);
$array[] = array('c','a','a',0);
$new_array =group_by_sub_array_key($array,3);
print_r($new_array);
function group_by_sub_array_key($array,$kn){
$new_array = array();
foreach($array AS $v){
$key=$v[$kn];
if(!array_key_exists($v[$kn],$new_array)){
$new_array[$key]=array();
}
unset($v[$kn]);
$new_array[$key][] = $v;
}
return $new_array;
}