Check if an object exists in an array

Question

I've got an array with multiple person-objects in it, this objects look like this:

id: 1,
name: 'Max Muster',
email: 'max.muster@example.com',
language: 'German'

Now, I've got objects in another array, which doesn't look exactly the same:

id: 1,
name: 'Max Muster',
email: 'max.muster@example.com',
language: 'de'

I've got a foreach-loop to loop through array 2 and check if the objects exists in array 1.

foreach($array2 as $entry) {
    if(existsInArray($entry, $array1)) {
        // exists
    } else {
        // doesn't exist
    }
}

Is there a function to check (like my existsInArray()), if my object exists in the array? I just need to check, if the object-id exists, other attributes doesn't matter.

As the objects are different, then you can't do a simple comparison to see if they are the same. What qualifies an object from the first array as matching an object from the second array? Same id? Same name? Same email? Same language? Some combination of those? — Mark Baker, May 30 '16 at 11:52
Yes, need to convert them Object to array than `array_diff`. — Murad Hasan, May 30 '16 at 11:52
You could make this a lot easier if you used the id's as the array keys. — jeroen, May 30 '16 at 11:54

score 19 · Accepted Answer · answered May 30 '16 at 12:00

19

Use the object IDs as keys when you put the objects in the array:

$array1[$object->id] = $object;

then use isset($array1[$object->id]) to check if the object already exists in $array:

if (isset($array1[$object->id])) {
    // object exists in array; do something
} else {
    // object does not exist in array; do something else
}

answered May 30 '16 at 12:00

axiac

68,258
9
99
134

this looks like it checks by index, but isn't index arbitrary? How does this work? – Urasquirrel Sep 14 '20 at 22:42
1

[PHP Arrays](https://www.yphp.net/manual/en/language.types.array.php) are, in fact, maps/hashes/dictionaries. They associate a numeric or string key to a value of any type. The OP has two sets of objects identified by their `id` attributes. The answer suggests to put the first set of objects in an array and use the `id` as key. When the second set of objects is processed, use the object `id` to find the object with the same `id` in the array. By using the `id` as key (and not a numeric key generated automatically), the object can be identified without scanning the entire array. – axiac Sep 15 '20 at 05:40

score 4 · Answer 2 · answered May 30 '16 at 11:55

4

It does not, but you can write it:

function existsInArray($entry, $array) {
    foreach ($array as $compare) {
        if ($compare->id == $entry->id) {
            return true;
        }
    return false;
}

answered May 30 '16 at 11:55

wogsland

9,106
19
57
93

score 0 · Answer 3 · answered May 30 '16 at 12:15

0

foreach($array2 as $entry) {
    if(in_array($entry, $array1)) {
        // exists
    }  else {
    // doesn't exist
    }
}

Use in_array to check if that particular object exists in the array

answered May 30 '16 at 12:15

User2403

317
1
5

score 0 · Answer 4 · answered May 01 '21 at 14:53

0

Use in_array

if(in_array($object, array)) {
   //exists
} else {
   //does not exist
}

answered May 01 '21 at 14:53

Check if an object exists in an array

4 Answers4

Linked