usort issue with decimal numbers

Question

I\'m currently trying to sort a multidimensional array by its subvalues. The structure of the array is:

[0] => Array
    (
        [id] => 87
        [         


        

Answer 1

Try strnatcmp():

usort($output, function($a, $b) {
    return strnatcmp($b->days_left, $a->days_left);
});

Answer 2

The PHP doc has a comment that has the solution to this problem. A big thanks to that guy.

Here is a function to sort multidimensional arrays with decimal numbers :

function usortWithFloatVals() {
    $arguments = func_get_args();
    $array = $arguments[0];
    $code = '';
    for ($c = 1; $c < count($arguments); $c += 2) {
        if (in_array($arguments[$c + 1], array("ASC", "DESC"))) {
            $code .= 'if ($a["'.$arguments[$c].'"] != $b["'.$arguments[$c].'"]) {';
            if ($arguments[$c + 1] == "ASC") {
                $code .= 'return ($a["'.$arguments[$c].'"] < $b["'.$arguments[$c].'"] ? -1 : 1); }';
            }
            else {
                $code .= 'return ($a["'.$arguments[$c].'"] < $b["'.$arguments[$c].'"] ? 1 : -1); }';
            }
        }
    }
    $code .= 'return 0;';
    $compare = create_function('$a,$b', $code);
    usort($array, $compare);
    return $array;
}

Use it just like how you use usort() :

usortWithFloatVals($data, function($a, $b) {
    return ($a[$_GET['sortby']] - $b[$_GET['sortby']]) ? 1 : -1;
});

Answer 3

See usort docs. Float result will be converted to integer. For correct work use this code:

usort(
    $data, 
    function($a, $b) {
        $result = 0;
        if ($a[$_GET['sortby']] > $b[$_GET['sortby']]) {
            $result = 1;
        } else if ($a[$_GET['sortby']] < $b[$_GET['sortby']]) {
            $result = -1;
        }
        return $result; 
    }
);