Arrays comparison in php

Question

I'm trying to compare two arrays, and extract some info of one of them and store it at another array (3rd). The structure of these two arrays looks like this:

Array(
[0] => stdClass Object
    (
        [Id] => 123
        [Size] => small
        [Color] => yellow
    )
[1] => stdClass Object
    (
        [Id] => 456
        [Size] => large
        [Color] => red
    )
[2] => stdClass Object
    (
        [Id] => 789
        [Size] => medium
        [Color] => blue
    )
)
Array
(
[0] => stdClass Object
    (
        [Id] => 456
        [Size] => large
        [Color] => red
        [Available] => true
    )

[1] => stdClass Object
    (
        [Id] => 123
        [Size] => small
        [Available] => false
    )
[2] => stdClass Object
    (
        [Id] => 789
        [Size] => medium
        [Color] => blue
        [Available] => true
    )
)

In the example, I need to store the property "available" only if the ID of these arrays are equal.

What I tried to do:

for (var $i = 0; $i < count($arrayA); $i++) {
    if ($ArrayA[$i]->Id == $arrayB[$i]->Id) {
        $getAvailable = $arrayB[$i]->Available;
    }
}

The problem:

Since we can have the situation where the property id in array A, position 0 is in a different position in array B, which can have a different structure, I have no idea how can I access the information I need (available), from one array comparing the ids of ArrayB and ArrayA.

I am sorry if I didn’t explain it better, because it’s a bit hard to put in words this situation, but let me know if you have any questions, and please, help me finding a solution :)

Desired array should look like this:

Array(
[0] => stdClass Object
(
    [Id] => 123
    [Size] => small
    [Color] => yellow
    [Available] => false
)

I edited the question and added this information in the end. @Dagon — Eduardo Pereira, Nov 11 '16 at 03:25
ah ok, that makes sense. any change of getting ID as the key to start with? if not its loop on array doing a search on the other for each id — , Nov 11 '16 at 03:27
http://stackoverflow.com/questions/6661530/php-multi-dimensional-array-search but it would probably be faster to loop the 2nd array first to use the Id as the key, then loop the first array — , Nov 11 '16 at 03:30
the problem is that if this array he mentioned has a lot more information than he put in the example, doing this loop may be too costly in terms of performance.. am I right?@Dagon — sergioviniciuss, Nov 11 '16 at 03:34
don't use `$ArrayA[$i]` since they won't lineup as usual, just use a simple `foreach`, then make an `if` comparison on the ids inside — Kevin, Nov 11 '16 at 03:36

Beginner · Accepted Answer · 2016-11-11T05:21:57.273

$arr1 = array(
    0 => (object)(array(
        'Id' => '123',
        'Size' => 'small',
        'Color' => 'yellow'
    )),
    1 => (object)(array
    (
        'Id' => '456',
        'Size' => 'large',
        'Color' => 'red'
    )),
    2 => (object)(array
    (
        'Id' => '789',
        'Size' => 'medium',
        'Color' => 'blue'
    ))
);
$arr2 = array(
    0 => (object)(array
    (
        'Id' => '456',
        'Size' => 'large',
        'Color' => 'red',
        'Available' => 'true'
    )),
    1 => (object)(array
    (
        'Id' => 123,
        'Size'=> 'small',
        'Available' => 'false'
    )),
    2 => (object)(array
    (
        'Id' => '789',
        'Size' => 'medium',
        'Color' => 'blue',
        'Available' => 'true'
    ))
);

First: declare a new variable array which will later stored your new structured array

$newArr = array();

Then you loop your first array $arr1

foreach($arr1 as $row1) {
}

then inside first loop make another loop which find it's match id from the second array $arr2 just compare there id and if it is match merge them

foreach($arr2 as $row2) {
   if ($row1->Id == $row2->Id) {
       // do something
   }
}

then push them but before you merge them you must convert them into an associative array

$newArr[] = array_merge((array)$row1, (array)$row2);

into your new array. and just stop the sub loop after you find it's match id using

break;

so your foreach loop would be like this

$newArr = array();
foreach($arr1 as $row1) {
    foreach($arr2 as $row2) {
        if ($row1->Id == $row2->Id) {
            $newArr[] = array_merge((array)$row1, (array)$row2);
            break;
        }
    }
}

This will be inefficient on large arrays but ok for small one — , Nov 12 '16 at 23:48

the_wizard · Answer 2 · 2016-11-11T03:48:44.500

0

This is not efficient for a large array but here you go

function getEqual($arrayA, $arrayB){

 foreach($arrayA as $aIndex => $aData){
     $id = $aData['Id'];
      $aData['Available'] = false;

     foreach($arrayB as $bIndex => $bData){
         if($id == $bData['Id']){
             $aData['Available'] = true;
         }
     }

     $arrayA[$aIndex] = $aData;
 }

 return $arrayA;

}

edited Nov 11 '16 at 03:48

answered Nov 11 '16 at 03:41

the_wizard

477
5
9

What would be efficient then? Could you give me a hint about techniques? (btw - the last curly brace slipped out of the code block) – stewo Nov 11 '16 at 03:45

Arrays comparison in php

2 Answers2