Regrouping arrays

[silkfire]

How do you solve this problem? I have a flat array that I need to transform into a 2D array where every fourth item is group together and contains 4 items.

 

From:

 

array(

          0,

          1,

          2,

          3,

          4,

          5,

          6,

          7,

          8,

          9,

          10,

          11,

          12,

          13,

          14,

          15

)

 

To:

 

array(

          array(0, 4, 8, 12),

          array(1, 5, 9, 13),

          array(2, 6, 10, 14),

          array(3, 7, 11, 15)

)

 

I'm sure there's some easy solution...

Note that I need to transform it, not create one from scratch.

[WebStyles]

hmmm... array_chunk will allow you to split into groups of 4 elements, but will maintain the same order as the original array... You could then re-organize them with a simple for() loop using the keys 0,1,2 and 3.

 

How is the original array built? (what values will it contain? just a sequence of numbers like your example? or can it contain other values or non-sequential values?)

 

[silkfire]

It will contain strings, does it matter? But they have to be grouped together logically, like I showed.

[WebStyles]

well, yes, it *did* matter. If it were always a sequence of numbers I would suggest a different approach.

 

In this case, try my first suggestion.

[silkfire]

Well actually what I showed you are the keys. What is your suggestion? Is there a way I could make a generic function where I can enter arguments for size of the groups and which Nth number to pick?

[WebStyles]

c'mon, just try what I suggested first, and then worry about wrapping it into a function.

 

<?php
$initialArray = array(0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15);
$chunks = array_chunk($initialArray, 4);
$final = array();
$key = 0;
foreach($chunks as $k=>$chunk){
for($i=0;$i<4;$i++){
	$final[$i][$key] = $chunk[$i];
}
$key++;
}
echo '<br>';
print_r($final);
?>