PHP Array Combination - One to many - php

Question

Sorry if a solution exists anywhere else, but I couldn't find one.
I have the following array:
$data = array(
array('a', 'b', 'c'),
array('e', 'f', 'g'),
array('w', 'x', 'y', 'z'),
);
I am trying hard to write a function that will give an array like:
a
e
w
x
y
z
f
w
x
y
z
g
w
x
y
z
b
e
w
x
y
z
f
w
x
y
z
g
w
x
y
z
c
e
w
x
y
z
f
w
x
y
z
g
w
x
y
z
The major problem here is that the number of source arrays and their lengths keep changing always. So a function should be capable of handling any data given to it.
I tried to come up with something like this:
function testfunc($data){
$arrayDepth = count($data);
foreach($data as $key=>$d){
foreach($d as $e){
echo $e . "\n";
if($key < $arrayDepth){
array_shift($data);
testfunc($data);
}
}
}
}
And the output I got was:
a
e
w
x
y
z
f
g
w
x
y
z
b
w
x
y
z
c
e
f
g
w
x
y
z
I am stuck for almost a day with no proper solution. Any help would be great! Thanks!

Answer 1

Recursion [Wikipedia] is your friend:
function product($arrays) {
if(count($arrays) === 1) {
return $arrays[0];
}
else {
$result = array();
foreach($arrays[0] as $value) {
$result[$value] = product(array_slice($arrays, 1));
}
return $result;
}
}
DEMO

Answer 2

Non-recursive version. This should run fast!
$result = end($data);
if ($result === false)
{
return false; // or Array or what makes sense for an empty array.
}
$higherArr = prev($data);
while ($higherArr !== false)
{
// Set the orignal array to be the one that you built previously.
$orig = $result;
$result = array();
foreach ($higherArr as $higherKey)
{
$result[$higherKey] = $orig;
}
$higherArr = prev($data);
}
echo 'Finished with: ' . var_export($result, true);