Array containing keys and associative array, how to make a relation

Question

I have an array which contains the path to a specific value from an other array, to make it a bit more clear, here is an exemple.

My array containing the keys which I'll call $params

Array
(
    [0] => paths
    [1] => assets
    [2] => js
)

And here is my associative array which I'll call $config

Array
(
    [paths] => Array
        (
            [assets] => Array
                (
                    [js] => /assets/js
                    [css] => /assets/css
                )

        )

    [library] => Array
        (
            [js] => jQuery
        )

)

So how could I use my array 1 to access the value in my array 2?

I tried $config[$params[0]][$params[1]][$params[2]], but it's not efficient at all.

Baba · Accepted Answer · 2012-12-26 10:48:53Z

2

You can try

$path = array(
        0 => 'paths',
        1 => 'assets',
        2 => 'js',
);


$data = array(
  'paths' => array(
    'assets' => array(
      'js' => '/assets/js',
      'css' => '/assets/css',
    ),
  ),
  'library' => array(
    'js' => 'jQuery',
  ),
);


$temp = $data;
foreach($path as $key) {
    $temp = $temp[$key];
}

var_dump($temp);

Output

string '/assets/js' (length=10)

edited Dec 26, 2012 at 10:48

answered Dec 26, 2012 at 10:42

Baba

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1 Comment

knittl Over a year ago

Aren't you overwriting the $data array, every time you assign a value to the $temp reference (which points to $data)?

Vishal Shah · Accepted Answer · 2012-12-26 10:54:26Z

1

Hi Jonathan here you have missed one brace in the end try this "$config[$params[0]][$params[1]][$params[2]]". It will work I am posting a code which worked fine for me

<?php
$params = array(0 => 'paths',1 => 'assets',2 => 'js');
echo '<pre>';print_r($params);

$config = array
(
    'paths' => array
        (
            'assets' => array
                (
                    'js' => '/assets/js',
                    'css' => '/assets/css'
                )

        ),

    'library' => array
        (
            'js' => 'jQuery'
        )

);
echo '<pre>';print_r($config);
echo $config[$params[0]][$params[1]][$params[2]];
 ?>

edited Dec 26, 2012 at 10:54

answered Dec 26, 2012 at 10:46

Vishal Shah

373 bronze badges

Comments

knittl · Accepted Answer · 2012-12-26 11:06:36Z

1

A loop should solve your problem:

$c = $config;
foreach($params as $path) {
  if(!array_key_exists($path, $c)) {
    $c = null;
    break;
  }
  $c = $c[$path];
}

This will iterate over every entry in $params and then access the subkey of the $config array. After finding it, $c will contain the current subarray. In the end, $c will contain the value you were looking for (NULL if the path was invalid/not found).

The same can be done in a functional way using the array_reduce function:

$path = array_reduce(function($current, $path) {
  if($current == NULL || !array_key_exists($path, $current))
    return NULL;

  return $current[$path];
}, $params, $config);

edited Dec 26, 2012 at 11:06

answered Dec 26, 2012 at 10:46

knittl

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