asort() problem

[Wagner]

$a['a'] = array('a' => '5');
$a['b'] = array('c' => '4');
$a['c'] = array('d' => '3');
$a['d'] = array('z' => '2');
$a['e'] = array('f' => '1');

asort($a);
print_r($a);

arsort($a);
print_r($a);

I made the array contents simpler, trying do understand. The 'z' instead of 'e' was introduced to create out of order in the analysis.  So, why on earth it results as below?  The keys sequence of asort most of the time result in D-B-A-C-E, no matter how much you change the letters and numbers, the arsort result in reverse order of the chaos, go figure !!!  The PHP version is 5.

 

Array
(
    [d] => Array
        (
            [z] => 2
        )

    => Array
        (
            [c] => 4
        )

    [a] => Array
        (
            [a] => 5
        )

    [c] => Array
        (
            [d] => 3
        )

    [e] => Array
        (
            [f] => 1
        )

)
Array
(
    [e] => Array
        (
            [f] => 1
        )

    [c] => Array
        (
            [d] => 3
        )

    [a] => Array
        (
            [a] => 5
        )

    => Array
        (
            [c] => 4
        )

    [d] => Array
        (
            [z] => 2
        )

 

 

 

[ginerjm]

As I read the manual for this function I sense that it doesn't work on multi-dimensional arrays. Why you get a consistent order while trying to do so I do not know, but I think you have to use a custom sorting function. See remarks for assort in the manual.

[Barand]

It would work for indexed arrays (they will sort on the value of the first item) but not for associative arrays like that one. It does work if the associative arrays have consistent key values for comparisonEG

$a['a'] = array('a' => '5');
$a['b'] = array('a' => '4');
$a['c'] = array('a' => '3');
$a['d'] = array('a' => '2');
$a['e'] = array('a' => '1');

That lack of consistency of array keys also make the custom sort option problematical too.

[Barand]

this will do it

$a['a'] = array('a' => '5');
$a['b'] = array('b' => '4');
$a['c'] = array('c' => '3');
$a['d'] = array('z' => '2');
$a['e'] = array('f' => '1');

echo '<pre>';
uasort($a, 'mysortASC');
print_r($a);

uasort($a, 'mysortDESC');
print_r($a);
echo '</pre>';

function mysortASC($a, $b)
{
    $atmp = array_values($a);
    $btmp = array_values($b);
    return $atmp[0] - $btmp[0];
}

function mysortDESC($a, $b)
{
    $atmp = array_values($a);
    $btmp = array_values($b);
    return $btmp[0] - $atmp[0];
}