Help with a bit of logic

[rossbarefoot]

I've got a situation that's driving me buggy. Maybe someone can give me a hand.

Given a multidimensional array like this:

$product_options = array( array("red","blue","green"),
array("small","medium","large"),
array("longsleeve","shortsleeve")
);

I need to end up with a an array of strings like this (consider each line to be a separate element in the array):

red:small:longsleeve
red:medium:longsleeve
red:large:longsleeve
red:small:shortsleeve
red:medium:shortsleeve
red:large:shortsleeve
blue:small:longsleeve

and so on, covering all potential combinations of the items in the array.

The $product_options array can contain any number of elements in any combinations.

I tend to think I would need to handle this with nested for loops and/or recursive functions, but I can't get my arms around this conceptually. Can anyone give me a nudge in the right direction?

Thanks for taking a look.

Ross

[pyfsapple]

Three for-loops:

$count0 = count($product_options[0]);
$count1 = count($product_options[1]);
$count2 = count($product_options[2]);

for($i=0;$i<$count0;$i++) {
    for($j=0;$j<$count1;$j++) {
        for($k=0;$k<$count2;$k++) {
            echo $product_options[0][$i].":".$product_options[1][$j].":".$product_options[2][$k]."<br>";
        }
    }
}

Try this...

[rossbarefoot]

Thanks for the suggestion.

This approach would be fine if the $product_options array were static. However the number of arrays that are contained within it may vary. I need an approach that is independent of knowing the number of arrays contained within $product_options.

Ross

[diego25]

I think you can use a recursive algorithm. Your base case would be if the argument is an array. If the argument is an array, call the function itself again. If the argument is not an array, do a loop and return the string.

Diego

[rossbarefoot]

A user on the PHPDN forums came up with some pseudo-code, and using that as a basis I wrote this, which works nicely:

<?php
$product_options = array( 	array("red","blue","green"),
							array("small","medium"),
							array("long","short") 
							);


$option_types_index = count($product_options);

if ($option_types_index < 0) {
	return "error";
}

$max_options_index = 1;

for ($x=0; $x < $option_types_index; $x++) {
	$max_index[$x] = count($product_options[$x]);
	$max_options_index *= $max_index[$x];
}

for ($x=0; $x < $max_options_index; $x++) {
	$current_index = $x % $max_index[0];
	$master_index = ($x - $current_index) / $max_index[0];
	$build_list = $product_options[0][$current_index];

for ($y=1; $y<$option_types_index; $y++) {
	$current_index = $master_index % $max_index[$y];
	$master_index = ($master_index - $current_index) / $max_index[$y];
	$build_list .= ":" . $product_options[$y][$current_index];
}

$option_list[] = $build_list;

}

?>

Here's the link to the other thread:
http://forums.devnetwork.net/viewtopic.php?p=29921#29921