Question

Question

How do you modify a value in a PHP array if you do not know the structure of the array in advance?

Example

In the following array, I have to change ‘fave_color’ to ‘blue’ in the part of the array where ‘system’ == ‘knoppix’ … the problem is I do not know what the structure of the array will be at runtime, so I cannot simply do:

$myarray['settings']['user_prefs']['otherhost']['fave_color'] = 'blue';

This will not work, because the nesting is unknown for the fave_color at runtime.

Moreover, the fave_color key I am interested in is dependent on system array key.

I have to find the one with the value ‘knoppix’ and then change the corresponding ‘fave_color’ value, making sure not to change any other fave_color value in the array.

'settings' => array(
  'user_prefs'=>array(
    'localhost'=>array(
      'fave_color'=>'orange',
      'system'    =>'unbuntu',
    ),
    'otherhost'=>array(
      'fave_color'=>'yellow',
      'system'    =>'knoppix',
    ),        
  ),
),

Answer 1

You can use array_walk_recursive and check if key is equal to ‘knoppix’.

function findKnoppix(&$value, $key)
{
    if($value == 'knoppix') $value = 'NEW VALUE';
}

array_walk_recursive($myArray, 'findKnoppix');