How to bring a chosen array key to the top of the array?

Question

Let's say I have an array as follows:

$food['fruit'] = array('apples','oranges','bananas');
$food['veg'] = array('potatoes','onions','peppers');
$food['meat'] = array('bacon','beef','chicken');

How would I go about ordering it such that any given type of food would be brought to the top of the array and the rest of the order remains intact?

So if the user selected 'veg' it'd change the order to:

$food = array('veg' => ..., 'fruit' => ..., 'meat' => ...);

Answer 1

This isn't a sort, since you only want to move one element, so:

• Use array_splice()to remove the element from the middle of the array.
• Then use array_unshift() to add it to the front of the array.

Answer 2

1. save this entry in tmp_val : $tmp_val = array('key'=>$food['key']);
2. unset this entry from array : unset($food['key']);
3. then use array_unshift to insert to the begining : array_unshift($food,$tmp_val)

Answer 3

You can create a new array, rearrange and replace old one:

$first = 'veg';

$tmp = array ($first => $food[$first]);
foreach ($food AS $key => $val) {
    if ($key != $first) {
        $tmp[$key] = $val;
    }
}

$food = $tmp;

or

$first = 'veg';

$tmp = array ($first => $food[$first]);
unset ($food[$first]);
$food = array_merge ($tmp, $food);

Answer 4

like this

$food = array_merge(array('veg' => $food['veg']), $food);

but the whole thing looks suspicious to me. Can you explain why you need this?

Answer 5

Avoid the loop:

$food['fruit'] = array('apples','oranges','bananas');
$food['veg'] = array('potatoes','onions','peppers');
$food['meat'] = array('bacon','beef','chicken');
$food['fish'] = array('code','haddock','plaice');

$key = 'veg';
if (array_key_exists($key,$food)) {
    $tmp[$key] = $food[$key];
    array_splice($food,array_search($key,array_keys($food)),1);
    $food = $tmp+$food;
}

echo '<pre>';
var_dump($food);
echo '</pre>';