如何根据不会出现在所有元素中的值对php数组进行排序？

问题描述：

I am having a php array as follows;

$array =Array(
[310] => Array
    (
        [vendorname] => Utsav the vendor
    )
[309] => Array
    (
        [vendorname] => Ashish vendor
        [suggest_order] => 1
    )
[308] => Array
    (
        [vendorname] => praveen rathod vendor
    )
[262] => Array
    (
        [vendorname] => Yash Vendor
        [suggest_order] => 0
    )
[264] => Array
    (
        [vendorname] => amol vendro
        [suggest_order] => 2
    ));

And I want to sort it based on suggest_order key so lowest suggest_order key's value should come first and than higher value and in last their comes all remaining elements which don't even have suggest_order key like;

$array =Array(
[262] => Array
    (
        [vendorname] => Yash Vendor
        [suggest_order] => 0
    )
[309] => Array
    (
        [vendorname] => Ashish vendor
        [suggest_order] => 1
    )
[264] => Array
    (
        [vendorname] => amol vendro
        [suggest_order] => 2
    )
[310] => Array
    (
        [vendorname] => Utsav the vendor
    )

[308] => Array
    (
        [vendorname] => praveen rathod vendor
    ));

I have tried PHP Sort Array By SubArray Value .

function cmp_by_optionNumber($a, $b) {
  return $a["suggest_order"] - $b["suggest_order"];
}
print_r(usort($array, "cmp_by_optionNumber"));

And I have also tried 2nd option in above answer,

$new_array=usort($array, function ($a, $b) {
    return $a['suggest_order'] - $b['suggest_order'];
});
print_r($new_array);

But I am getting "1" in response; Any help will be appreciated.

答

All sort methods take the array to sort as reference. So you don't have to care about the return value, as the sorting is done in place.

function cmp_by_optionNumber($a, $b) {
  return $a["suggest_order"] - $b["suggest_order"];
}
usort($array, "cmp_by_optionNumber");
print_r($array);

If you need to do some special handling for suggest_order, you could use isset inside the sort function.

usort($array, function($a, $b) {
    if (isset($a["suggest_order"]) && isset($b["suggest_order"])) {
        return $a["suggest_order"] - $b["suggest_order"];
    }
    if (isset($a["suggest_order"])) {
        return -1;
    }
    if (isset($b["suggest_order"])) {
        return 1;
    }
    return 0;
});

答

to compare elements which have 'suggest_order' property with those which doesn't have you can use function like:

function cmp_by_optionNumber($a, $b) {
   $lval = $a["suggest_order"]??-1;
   $rval = $b["suggest_order"]??-1;
    return $lval > $rval ? 1 : $rval > $lval ? -1 : 0;
}

this will properly order items as you want - by suggest_order key

also you do not want to print result of sort function but original array passed to sort function to see if it's sorted

如何根据不会出现在所有元素中的值对php数组进行排序？

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