Sort a 2d array containing only one column and preserve first level keys

I need to sort an array like

$arrayName = array(
    0 => array('val' => 100),
    1 => array('val' => 75),
    3 => array('val' => 10),
    4 => array('val' => 15)
);

I need output like this

$arrayName = array(
    3 => array('val' => 10),
    4 => array('val' => 15),
    1 => array('val' => 75),
    0 => array('val' => 100)
);

asort() should work for you because it will:

• sort by row element count (all rows have a count of 1), then sort by column values from left to right (you only have one column), and
• preserve the original first level keys.

$arrayName = array(
    0 => array('val' => 100),
    1 => array('val' => 75),
    3 => array('val' => 10),
    4 => array('val' => 15)
);
asort($arrayName);
    
print_r($arrayName);

Output:

Array (
    [3] => Array ( [val] => 10 )
    [4] => Array ( [val] => 15 )
    [1] => Array ( [val] => 75 )
    [0] => Array ( [val] => 100 )
)

For a descending sort, use arsort().