How to recursively create a multidimensional array? - php

Question

I am trying to create a multi-dimensional array whose parts are determined by a string. I'm using . as the delimiter, and each part (except for the last) should be an array
ex:
config.debug.router.strictMode = true
I want the same results as if I were to type:
$arr = array('config' => array('debug' => array('router' => array('strictMode' => true))));
This problem's really got me going in circles, any help is appreciated. Thanks!

Answer 1

Let’s assume we already have the key and value in $key and $val, then you could do this:
$key = 'config.debug.router.strictMode';
$val = true;
$path = explode('.', $key);
Builing the array from left to right:
$arr = array();
$tmp = &$arr;
foreach ($path as $segment) {
$tmp[$segment] = array();
$tmp = &$tmp[$segment];
}
$tmp = $val;
And from right to left:
$arr = array();
$tmp = $val;
while ($segment = array_pop($path)) {
$tmp = array($segment => $tmp);
}
$arr = $tmp;

Answer 2

I say split everything up, start with the value, and work backwards from there, each time through, wrapping what you have inside another array. Like so:
$s = 'config.debug.router.strictMode = true';
list($parts, $value) = explode(' = ', $s);
$parts = explode('.', $parts);
while($parts) {
$value = array(array_pop($parts) => $value);
}
print_r($parts);
Definitely rewrite it so it has error checking.

Answer 3

Gumbo's answer looks good.
However, it looks like you want to parse a typical .ini file.
Consider using library code instead of rolling your own.
For instance, Zend_Config handles this kind of thing nicely.

Answer 4

I really like JasonWolf answer to this.
As to the possible errors: yes, but he supplied a great idea, now it is up to the reader to make it bullet proof.
My need was a bit more basic: from a delimited list, create a MD array. I slightly modified his code to give me just that. This version will give you an array with or without a define string or even a string without the delimiter.
I hope someone can make this even better.
$parts = "config.debug.router.strictMode";
$parts = explode(".", $parts);
$value = null;
while($parts) {
$value = array(array_pop($parts) => $value);
}
print_r($value);

Answer 5

// The attribute to the right of the equals sign
$rightOfEquals = true;
$leftOfEquals = "config.debug.router.strictMode";
// Array of identifiers
$identifiers = explode(".", $leftOfEquals);
// How many 'identifiers' we have
$numIdentifiers = count($identifiers);
// Iterate through each identifier backwards
// We do this backwards because we want the "innermost" array element
// to be defined first.
for ($i = ($numIdentifiers - 1); $i >=0; $i--)
{
// If we are looking at the "last" identifier, then we know what its
// value is. It is the thing directly to the right of the equals sign.
if ($i == ($numIdentifiers - 1))
{
$a = array($identifiers[$i] => $rightOfEquals);
}
// Otherwise, we recursively append our new attribute to the beginning of the array.
else
{
$a = array($identifiers[$i] => $a);
}
}
print_r($a);