How to sort php array based on value which will not be present in all elements?

Question

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.

You can either use null coalesce (??) or check if each side has ['suggest_order'] set and decide how this will affect the test (i.e. what dummy value you want it to have to move it into the right place) — Nigel Ren, Apr 18 '18 at 11:02
Possible duplicate of [php sort($array) returning 1 instead of sorted array](https://stackoverflow.com/questions/28957927/php-sortarray-returning-1-instead-of-sorted-array) — Philipp Maurer, Apr 18 '18 at 11:02
from docs `Returns TRUE on success or FALSE on failure` and if you see it takes the array as reference `bool usort ( array &$array , callable $value_compare_func )` that means your given array will be already sorted. — Edwin, Apr 18 '18 at 11:04
Possible duplicate of [Sort Multi-dimensional Array by Value](https://stackoverflow.com/questions/2699086/sort-multi-dimensional-array-by-value) — Muhammad Abdullah, Apr 18 '18 at 11:07
@AbdullahMalik He linked a multi dimensional sort question in his question and uses the given answer in his code. The problem he describes has nothing to do with multi dimensional sorting. — Philipp Maurer, Apr 18 '18 at 11:10
Possible duplicate of [sorting array based on inner-array key-value](https://stackoverflow.com/questions/6530631/sorting-array-based-on-inner-array-key-value) — Nishit Manjarawala, Apr 18 '18 at 11:34

Philipp · Accepted Answer · 2018-04-18T11:04:50.387

2

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;
});

edited Apr 18 '18 at 11:04

answered Apr 18 '18 at 11:00

Philipp

15,377
4
35
52

2

What about the problem when an element doesn't have a `"suggest_order"`? – KIKO Software Apr 18 '18 at 11:02
Thanx @Phillipp but I am getting 0,blank,blank,1,2 this kind of sorted array. – Ahmed Syed Apr 18 '18 at 11:05
@MujahedAKAS which code did you tried? yours or my code with the suggestion_order handling? – Philipp Apr 18 '18 at 11:06
this is wrong, you cannot substract suggest orders as one may be 10 and other 1, you need to order by suggest_order, check my answer, it won't sort array at all – bestestefan Apr 18 '18 at 11:07
@stetoc of couse you can - the result don't have to be exactly -1, 0 or 1 - it just have to be positive, negative or zero, which is the case, if you just subtract the values – Philipp Apr 18 '18 at 11:09
after thinking for a while it may work, I missthinked it, ik that it has to be > 0 or < 0 or 0 to sort, but I had few cases in my head where it would not order items properly, maybe just my mistake – bestestefan Apr 18 '18 at 11:12
If OP is getting the results he says, perhaps swap the -1 and 1 from the dummy return values. This may push the empty ones to the end. – Nigel Ren Apr 18 '18 at 11:13

bestestefan · Answer 2 · 2018-04-18T11:09:32.550

-1

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

edited Apr 18 '18 at 11:09

answered Apr 18 '18 at 11:07

bestestefan

852
6
20

While this is an improvement to the code of OP, this does not answer the question in any way. – Philipp Maurer Apr 18 '18 at 11:08
works in php 7, in previous versions you need to use `array_key_exists('suggest_order', $array) ? $array['suggest_order'] : -1;` – bestestefan Apr 18 '18 at 11:33

How to sort php array based on value which will not be present in all elements?

2 Answers2