Question

Please could you help me:

i have an array sorted by key:

$a['a'] = value;
$a['b'] = value;
$a['c'] = value;
$a['d'] = value;
$a['e'] = value;

I need reordeer this by this rule – take one field and put it on first place and another do not change

f.e.

$a['c'] = value;
$a['a'] = value;
$a['b'] = value;
$a['d'] = value;
$a['e'] = value;

or

$a['d'] = value;
$a['a'] = value;
$a['b'] = value;
$a['c'] = value;
$a['e'] = value;

Answer 1

I think you meant something like this:

function get_and_place_first($index, $array) {
    $new_first_element = $array[$index];       // save element you want to have as first
    unset($array[$index]);                     // delete that element from old position
    array_unshift($array, $new_first_element); // place it at the beginning of $array
}

You should use it in this way:

get_and_place_first('c', $a);

and you should get desired effect from your first example. Of course you may want to check if element exists in given array etc., but it’s up to you.