Array Unique for Array of Objects with exclude option for certain keys in Object

Question

I have an Object Array with few fields.

I was able to get the Array unique for this Object Array using below code:

$aa = array_unique($dd,SORT_REGULAR);

But what i am trying to achieve is, i want to exclude certain keys in object from "unique check". Lets say all object values are matching except "valid_from" and "valid_to" date fields.

Below is array structure:

Array
(
    [9948] => stdClass Object
        (
            [payrate] => 78.00000
            [valid_from] => 03/01/2017
            [valid_to] => 03/31/2017
        )

    [15133] => stdClass Object
        (
            [payrate] => 78.00000
            [valid_from] => 04/01/2017
            [valid_to] => 04/31/2017
        )

)

So as per above case as my pay rate is same in both object, but as valid from and valid to are different it will be still considered different entries.

Is there anyway we can specify exclude certain fields out for Array Unique for Array of Objects.

Kyoya · Answer 1 · 2017-03-30T22:14:02.563

You can use array_filter with a custom callback to filter out some elements from an array.

All you have to do is to implement your filter logic. Here a simple example:

<?php
$array = json_decode(
    '[{"name":"foo","count":2},{"name":"foo","count":10},{"name":"baz","count":5},{"name":"foobar","count":10}]'
);

$uniqueCheck = [];

$filtered = array_filter(
    $array,
    function ($element) use (&$uniqueCheck) {
        if (isset($uniqueCheck[$element->name])) {
            return false;
        }

        $uniqueCheck[$element->name] = true;

        return true;
    }
);

print_r($array);
print_r($filtered);

This will produce:

Array
(
    [0] => stdClass Object
        (
            [name] => foo
            [count] => 2
        )

    [1] => stdClass Object
        (
            [name] => foo
            [count] => 10
        )

    [2] => stdClass Object
        (
            [name] => baz
            [count] => 5
        )

    [3] => stdClass Object
        (
            [name] => foobar
            [count] => 10
        )

)

Array
(
    [0] => stdClass Object
        (
            [name] => foo
            [count] => 2
        )

    [2] => stdClass Object
        (
            [name] => baz
            [count] => 5
        )

    [3] => stdClass Object
        (
            [name] => foobar
            [count] => 10
        )

)

Edit: Changed $element->count based check to "unique $element->name check".

awesome let me try this out, and will let you know! thank you! — Wolverine, Mar 30 '17 at 21:51
If you need help with `array_filter`, in my answer it is linked to the PHP manual. — Kyoya, Mar 30 '17 at 21:56
This will check for that value in count right? but how will be exclude count from this callback function? — Wolverine, Mar 30 '17 at 22:04

score 0 · Accepted Answer · edited May 23 '17 at 12:25

0

See also array_unique for objects?

In case you work with non-stdClass object you could implement __toString to use array_unique to filter.

To filter on unique stdClass, using only a few of the attributes you could try something like:

From PHP 7 onwards you could use array_column to get a value from a stdClass, so if you use PHP7:

array_unique(array_column($array,'payrate'));

Before PHP 7 you could try:

array_unique(array_map(function($item) {return $item->payrate;},$array);

In case there are more attributes to compare there are different ways. array_reduce is just one of them.

The outcome of this one will not have any duplicates. So if all attributes match, the item will be filtered.

$attributes = ['payrate','date']
$filtered = array_reduce($array,function($carry,$item) use ($attributes) {
    if(count(array_filter($attributes,function ($attribute) use ($carry, $item) {
            return !in_array($item->$attribute,array_map(function($carriedItem) use ($attribute) {
                return $carriedItem->$attribute;
            },$carry));
        }))) {
        $carry[] = $item;
    }
    return $carry;
},[]);

see http://sandbox.onlinephpfunctions.com/code/5f8171d76362ada7e165afeaadbecffc6cdd497a

edited May 23 '17 at 12:25

Community

1
1

answered Mar 30 '17 at 22:18

Maarten van Middelaar

1,691
10
15

What if there are multiple fields like payrate, lets say hours,date etc ? – Wolverine Mar 30 '17 at 22:30
1

Yes indeed, I didn't test the last bit. – Maarten van Middelaar Mar 31 '17 at 07:42
Awesome man you are genius , tweaked it to my requirement and it worked! – Wolverine Mar 31 '17 at 14:00
I'm glad to help. I don't get to use array_reduce, array_filter and array_map in one function too often ;-) – Maarten van Middelaar Mar 31 '17 at 20:48
Otherwise, check this scenario: http://sandbox.onlinephpfunctions.com/code/44705c4c99107f122a8405b3f95b73eb1c086d03 It looks like three different different values, but because both values are present in one of the previous, the third class is not included in the result. I think this is unwanted behavior – Maarten van Middelaar Mar 31 '17 at 20:56
awesome can we maintain the index of array if these array objects are indexed with integer values say 12345? – Wolverine Apr 04 '17 at 16:47

Array Unique for Array of Objects with exclude option for certain keys in Object

2 Answers2