Compare Two Array - Delete Matching values

Question

I need to search $array_2 for a json_encode()'d value from $array_1.

If item_id in $array_1 does not match the item_id in the some_field field in $array_2 then I need that array index so I can insert that into the database.

I've tried using in_array() but that won't work because the arrays have different keys. Also array_diff() will not work because the array indexes have no relation.

$array_1:

Array
(
    [0] => Array
        (
            [id] => 34
            [item_id] => sfg4et4
        )

    [1] => Array
        (
            [id] => 472
            [item_id] => adadgt4
        )
)

$array_2;

Array
(
    [0] => Array
        (
            [some_field] => {"item_id":"mlkjm980"}
        )

    [1] => Array
        (
            [some_field] => {"item_id":"fsff5ssa"}
        )
)

Do the numerical indexes in these arrays have any correlation? For example do you only want to compare item at index 0 in array 1 to item in index 0 in array 2? If so, are the arrays guaranteed to be the same size? — Mike Brant
– Mike Brant, Commented Dec 11, 2013 at 19:07
No, they don't. Sorry I did not include that. So array_diff() will not work either. — Draven
– Draven, Commented Dec 11, 2013 at 19:10

Mike Brant · Accepted Answer · 2013-12-11 19:27:24Z

2

It seems to me that the first step would be to put $array_2 into a usable form. To do this, I might suggest using array_walk() to rewrite this array to be solely a numerically indexed array of item_id values.

$array_2 = [...];

array_walk($array_2, function(&$value, $index_not_used) {
    $some_field = json_decode($value['some_field']);
    // overwrite value
    $value = $some_field->item_id;
});

$array_2 is now an array like ['mlkjm980','fsff5ssa', ...]

Now you can apply array_filter() to $array_1 using this modified $array_2 array.

$filtered_array = array_filter($array_1, function ($value) use ($array_2) {
    $item_is_in_array_2 = in_array($value['item_id'], $array_2);
    return !$item_is_in_array_2; // return negation of value as we want to filter out cases where item_id is in $array_2
});

edited Dec 11, 2013 at 19:27

answered Dec 11, 2013 at 19:20

Mike Brant

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6 Comments

Draven Over a year ago

I did something almost just like that )you can see my edit) but the problem is I'll still need the values from $array_1 so I can insert it into the database.

Mike Brant Over a year ago

@Draven This solution I provided gives you that, as $filtered_array is just subset of $array_1 with matches removed.

Draven Over a year ago

Oh. I'll be back in an hour or so and I'll give it a shot. Thanks!

Draven Over a year ago

Any way I can get the id field after? I need it for later on in the script to UPDATE the database instead of INSERT.

Mike Brant Over a year ago

@Draven The id field would still remain in the filtered array. Again, this approach does not modify the individual array elements in $array_1 at all, it simply removes the elements you want to filter out.

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