Swap array values with php

Question

I have an array:

array(
    0 => \'contact\',
    1 => \'home\',
    2 => \'projects\'
);

and I need to swap the \'contact\' with

Answer 1

If you don't want to use another variable:

    $array[0] = $array[0] + $array[1];
    $array[1] = $array[0] - $array[1];
    $array[0] = $array[0] - $array[1];

Answer 2

$x = array('a', 'b', 'c', 'd');
array_splice($x, 1, 2, array_reverse(array_slice($x, 1, 2)));
var_dump($x);

array_splice can replace a reversed array_slice

Answer 3

In PHP 7.1+ syntax, you can use this

[$Array[$a], $Array[$b]] = [$Array[$b], $Array[$a]];

Answer 4

Just use a temp variable to hold it. So:

$temp = $array[0];
$array[0] = $array[1];
$array[1] = $temp;

That way you don't lose the value of one of them.

Answer 5

I wrote simple function array_swap: swap two elements between positions swap_a & swap_b.

function array_swap(&$array,$swap_a,$swap_b){
   list($array[$swap_a],$array[$swap_b]) = array($array[$swap_b],$array[$swap_a]);
}

For OP question (for example):

$items = array(
  0 => 'contact',
  1 => 'home',
  2 => 'projects'
);

array_swap($items,0,1);
var_dump($items);
// OUTPUT

array(3) {
   [0]=> string(4) "home"
   [1]=> string(7) "contact"
   [2]=> string(8) "projects"
 }

Update Since PHP 7.1 it's possible to do it like:

$items = [
  0 => 'contact',
  1 => 'home',
  2 => 'projects'
];

[$items[0], $items[1]] = [$items[1], $items[0]];

var_dump($items);
// OUTPUT

array(3) {
   [0]=> string(4) "home"
   [1]=> string(7) "contact"
   [2]=> string(8) "projects"
 }

It's possible through Symmetric array destructuring.

Answer 6

Just use a temp variable to hold one value as you swap the other. Then restore the first with the temp variable. For numbers there are other methods that don't require the use of temp variables but here it's the best (only?) way.

$a = array(
    0 => 'contact',
    1 => 'home',
    2 => 'projects'
);

print_r($a);
Array ( [0] => contact [1] => home [2] => projects )

$tmp = $a[0];
$a[0] = $a[1];
$a[1] = $tmp;

print_r($a);
Array ( [0] => home [1] => contact [2] => projects )