Question

This is actually a problem that I’ve already solved, but I suspect that there may be a better solution. I have a nested array which basically represents a list of all the nodes from a category tree (in no particular order):

Array(     [0] => Array(         [Category] => Array(             [id] => 49             [name] => Poster         )         [Child] => Array()     )     [1] => Array(         [Category] => Array(             [id] => 48             [name] => Sticker         )         [Child] => Array()     )     [2] => Array(         [Category] => Array(             [id] => 46             [name] => Hat         )         [Child] => Array()     )     [3] => Array(         [Category] => Array(             [id] => 45             [name] => Hoodie         )         [Child] => Array()     ) ) 

You’ll notice that $node['Child'] is an empty array in all instances. This is because I’ve already used array_filter() to filter out all non-leaf-nodes. Still, what I ultimately want is to have a single-dimensional array of the leaf nodes like this:

Array(     [49] => Poster     [48] => Sticker     [46] => Hat     [45] => Hoodie ) 

So what would be the most elegant way of converting the first array to the second array?

Optionally, you can also start with an array of both leaf-nodes and non-leaf-nodes, and try to both prune the array and restructure it. An example of a non-leaf-node would be something like:

[7] => Array(     [Category] => Array(         [id] => 36         [name] => Merch     )     [Child] => Array(         [0] => Array(             [id] => 49             [name] => Poster         )         [1] => Array(             [id] => 48             [name] => Sticker         )         [2] => Array(             [id] => 40             [name] => Apparel         )     ) ) 

Lastly, I’m using CakePHP, so use of CakePHP’s Set class is also acceptable.

Answer 1

Elegant? Define elegant. I think some people are going to turn this into a golf contest as opposed to simply doing what makes sense and is evident to anyone stumbling upon the code later on:

$cats = array(); foreach($categories as $c) {     $cats[$c['Category']['id']] = $c['Category']['name']; } 

I suspect this is what you have, in which case I suggest you pat yourself in the back and move on.