Compare and Update PHP array

Question

I have two arrays in PHP:

Array 1

Array
(
    [0] => Array
        (
            [autoid] => t35wmkbg
            [task] => Zaphod
            [progress] => incomplete
        )

    [1] => Array
        (
            [autoid] => cwg2yc5q
            [task] => Arthur
            [progress] => incomplete
        )

    [2] => Array
        (
             [autoid] => 85q4bcmy
             [task] => Ford
             [progress] => incomplete
        )

    [3] => Array
        (
             [autoid] => yc5qcwg2
             [task] => Trillian
             [progress] => incomplete
        )
)

Array 2

Array
(
    [0] => Array
        (
            [autoid] => t35wmkbg
            [task] => Zaphod
            [progress] => complete
        )

    [1] => Array
        (
            [autoid] => 85q4bcmy
            [task] => Ford
            [progress] => incomplete
        )

    [2] => Array
        (
            [autoid] => cwg2yc5q
            [task] => Arthur
            [progress] => pending
        )

)

I need to:

• Step through Array 1, and check if the autoid exists in Array 2.
• If it does exist, update the progress field to match.

So the ideal output when using the arrays above would be:

Array 3

Array
(
    [0] => Array
        (
            [autoid] => t35wmkbg
            [task] => Zaphod
            [progress] => complete
        )


    [1] => Array
        (
            [autoid] => cwg2yc5q
            [task] => Arthur
            [progress] => pending
        )

    [2] => Array
        (
             [autoid] => 85q4bcmy
             [task] => Ford
             [progress] => incomplete
        )
 
    [3] => Array
        (
             [autoid] => yc5qcwg2
             [task] => Trillian
             [progress] => incomplete
        )

)

I am not sure how best to go about this, if anyone has any thoughts or pointers that would be awesome.

question from:https://stackoverflow.com/questions/65843734/compare-and-update-php-array

Answer 1

First change the arr2 so its index is the autoid then you can use it easily to get the progress value. Then just foreach over arr1 and apply changes to progress if they exist

$arr1 = [
            ['autoid' => 't35wmkbg','task' => 'Zaphod','progress' => 'incomplete'],
            ['autoid' => 'cwg2yc5q', 'task' => 'Arthur', 'progress' => 'incomplete'],
            ['autoid' => '85q4bcmy', 'task' => 'Ford', 'progress' => 'incomplete'],
            ['autoid' => 'yc5qcwg2', 'task' => 'Trillian', 'progress' => 'incomplete']
        ];

$arr2 = [
            ['autoid' => 't35wmkbg', 'task' => 'Zaphod', 'progress' => 'complete'],
            ['autoid' => '85q4bcmy', 'task' => 'Ford', 'progress' => 'incomplete'],
            ['autoid' => 'cwg2yc5q', 'task' => 'Arthur', 'progress' => 'pending']
        ];

#first make arr2 indexable on the autoid
foreach ($arr2 as $a) {
    $arr2search[$a['autoid']] = $a;
}

foreach ($arr1 as $a){
    // do we have an autoid in arr2
    if ( isset($arr2search[$a['autoid']])){
        $a['progress'] = $arr2search[$a['autoid']]['progress'];
    }
    $merged[] = $a;
    
}

print_r($merged);

RESULT

Array
(
    [0] => Array
        ([autoid] => t35wmkbg,  [task] => Zaphod,  [progress] => complete)

    [1] => Array
        ([autoid] => cwg2yc5q, [task] => Arthur, [progress] => pending )

    [2] => Array
        ([autoid] => 85q4bcmy,  [task] => Ford,  [progress] => incomplete )

    [3] => Array
        ([autoid] => yc5qcwg2, [task] => Trillian, [progress] => incomplete )
)