سؤال

First, I have to list what I have found

How to Remove Array Element and Then Re-Index Array?

PHP reindex array?

They did not make sense in my case. I have fallen into ridiculous request and I've force to find the way out, then please don't ask me why I want to do that.

I have below array

$input = array(
          0=>array('a', 'b'=>array('c')),
          1=>array('b', 'c'=>array('d')),
          2=>array('c', 'd'=>array('e')),
        );

I want to increase all of keys by 1 or decrease by 1 (acceptable to index is negative int number)

Here is expected result

//after increased by 1
$input = array(
          1=>array('a', 'b'=>array('c')),
          2=>array('b', 'c'=>array('d')),
          3=>array('c', 'd'=>array('e')),
        );

or

//after decreased by 1
$input = array(
          -1=>array('a', 'b'=>array('c')),
          0=>array('b', 'c'=>array('d')),
          1=>array('c', 'd'=>array('e')),
        );

The closet answer I got here from raina77ow in the question How to increase by 1 all keys in an array?

$arr = array_flip(array_map(function($el){ return $el + 1; }, array_flip($arr)));

But it just works with simple array key pairs, if array value is other array instead of a string or integer, it would raise the exception

array_flip(): Can only flip STRING and INTEGER values!

The thing what I could think is handling the array to swap roster manually, it would be the final way if there were not any other workaround.

Any help is appreciated!

هل كانت مفيدة؟

المحلول 2

The easiest way would probably to use foreach and make a new array... like this:

$new = array();
foreach($arr as $k=>$v) {
    $new[$k+1] = $v; // either increase
    $new[$k-1] = $v; // or decrease
}

You can also perform the operation by passing the original array by reference.

نصائح أخرى

This should so the trick.

    // Increase by one
    $input = array_combine(
        array_map(function($value) {
            return $value += 1;
        }, array_keys($input)), $input
    );
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