Question

I have an array of strings that are formatted like this:

$strings = array(
   "/user",
   "/robot",
   "/user/1",
   "/user/2",
   "/user/2/test",
   "/robot/1"
);

What I need to do is turn this into an array of the following structure when I print_r() it:

Array
(
  [user] => Array (
    [1] => array(),
    [2] => Array (
      [test] => array()
    )
  [robot] => Array (
      [1] => array()
    )
)

I know I need to explode the original string by delimiter /. However my problem is how do I then build the dynamic array.

Please note that the strings could potentially have an unlimited amount of slashes.

Answer 1

You can use a reference to progressively build an array as you traverse through the list.

$strings = array(
   "/user",
   "/robot",
   "/user/1",
   "/user/2",
   "/user/2/test",
   "/robot/1"
);

$extracted = array();

foreach( $strings as $string )
{
  $pos =& $extracted;
  foreach( explode('/', ltrim($string, '/')) as $split )
  {
    if( ! isset($pos[$split]) )
    {
      $pos[$split] = array();
    }

    $pos =& $pos[$split];
  }
}

print_r($extracted);

This code might not handle empty elements very well (e.g., /user//4//////test), depending on your requirements.