以递归方式从多维数组中删除特定键

Question

I am trying to create a function to remove keys from a dynamic multidimensional array, i need to give:

removeByIndex(['hello', 'my', 'world']);

And then the function needs to do this:

unset($array['hello']['my']['world']);

The number of indexes are dynamic, example:

removeByIndex(['hello', 'my']); // Do: unset($array['hello']['my']);
removeByIndex(['hello']); // Do: unset($array['hello']);

I tried to use some foreach loops, but i didn't find a solution yet.

Any help will be welcome.

Answer 1

No need for eval() with a little bit of referencing.

/**
 * Remove index from multi-dimensional array.
 *
 * @param array $array
 *   The array to remove the index from.
 * @param array $indices
 *   Indexed array containing the indices chain up to the index that should be
 *   removed.
 * @return
 *   The array with the index removed.
 * @throws \InvalidArgumentException
 *   If the index does not exist within the array.
 */
function removeByIndex(array $array, array $indices) {
  // Create a reference to the original array.
  $a =& $array;

  // Count all passed indices, remove one because arrays are zero based.
  $c = count($indices) - 1;

  // Iterate over all passed indices.
  for ($i = 0; $i <= $c; ++$i) {
    // Make sure the index to go down for deletion actually exists.
    if (array_key_exists($indices[$i], $a)) {
      // This is the target if we reached the last index that was passed.
      if ($i === $c) {
        unset($a[$indices[$i]]);
      }
      // Make sure we have an array to go further down.
      elseif (is_array($a[$indices[$i]])) {
        $a =& $a[$indices[$i]];
      }
      // Index does not exist since there is no array to go down any further.
      else {
        throw new \InvalidArgumentException("{$indices[$i]} does not exist.");
      }
    }
    // Index does not exist, error.
    else {
      throw new \InvalidArgumentException("{$indices[$i]} does not exist.");
    }
  }

  return $array;
}

print_r(removeByIndex(
  [ "test1" => [ "test2" => [ "test3" => "test" ] ], "test4" => "test" ],
  [ "test1", "test2", "test3" ]
));

Since I mentioned it in the comments, one could (micro-)optimize the function, but I advice against it, since it is less readable and might confuse some programmers.

<?php

function removeByIndex(array $array, array $indices) {
  $a =& $array;
  $c = count($indices) - 1;
  $i = 0;
  do {
    if (array_key_exists($indices[$i], $a)) {
      if ($i === $c) {
        unset($a[$indices[$i]]);
        return $array;
      }
      elseif (is_array($a[$indices[$i]])) {
        $a =& $a[$indices[$i]];
      }
      else break;
    }
    else break;
  }
  while (++$i);
  throw new \InvalidArgumentException("{$indices[$i]} does not exist.");
}