Create dynamically named variables based on array keys - php

Question

I have a multidimensional array and I want to create new variables based on the keys.
I have written this code, but it returns NULL:
$a = array("test" => array("a", "b", "c"));
foreach($a as $key => $value){
if(is_array($value)){
$i = 0;
foreach($value as $v){
$i++;
$$key[$i] = $v;
}
}
}
var_dump($test);
?>
Where is the problem?

Answer 1

Make that:
${$key}[$i] = $v;
$$key[$i] means "the variable whose name is $key[$i]".
${$key}[$i] means "position $i from the variable whose name is $key".
Also, it would be nice if you could initialize that $test array, so you won't get notices. Add the following before the second foreach:
$$key = array();

Answer 2

+1 to #Radu's answer, but you should also think about if these solutions would work for you:
$a = array("test" => array("a", "b", "c"));
foreach($a as $key => $value){
if(is_array($value)){
$$key = array_values($value);
}
}
var_dump($test);
Or:
$a = array("test" => array("a", "b", "c"));
extract($a);
var_dump($test);
See: array_values(), extract().

Answer 3

$$key[$i] tries to get the variable whose name matches the value of $key[$i]. You could get a reference to $$key first, and then add an item to that reference:
$a = array("test" => array("a", "b", "c"));
foreach($a as $key => $value){
if(is_array($value)){
$i = 0;
foreach($value as $v){
$i++;
$x = & $$key;
$x[$i] = $v;
}
}
}
var_dump($test);
?>
[edit]
But I see, I'm somewhat slow in testing and writing an answer, since another good answer has been posted minutes ago. Still keeping this, since it uses a different and not much more complex approach.