Remove unwanted elements from subarrays in multidimensional array

Question

I have a multidimensional array like this:

[
    [
        'id' => 1,
        'name' => 'John',
        'address' => 'Some address 1'
        'city' => 'NY'
    ],
    [
        'id' => 2,
        'name' => 'Jack',
        'address' => 'Some address 2'
        'city' => 'NY'
    ]
    ...
  
    [ ... ]
]

How can I remove elements in all subarrays and only retain the id and name keys with their values?

Astir

Do you actually need filtering (by some value) or are you looking to simply extract the two keys? – Lanate

maybe the wrong term "filter" - what i'm lookng for is keeping only those 2 keys in that multidim array – Astir

Loop and unset all other. or use array_column – Calandracalandria

A simple foreach where you build a new array would be the best choice if you also want to keep the original array intact. – Lanate

Answer 1

Would this work?

$result = array_map(function($arr) {
    return [
        'id' => $arr['id'],
        'name' => $arr['name']
    ];
}, $orig_array);

Smoot

Answer 2

You want to retain the first two associative elements, so you can make array_slice() calls within array_map(). (Demo)

var_export(
    array_map(fn($row) => array_slice($row, 0, 2), $array)
);

---

Or mapped called of array_intersect_key() against an establish whitelist array. (Demo)

$keep = ['id' => '', 'name' => ''];
var_export(
    array_map(
        fn($row) => array_intersect_key($row, $keep),
        $array
    )
)

---

Or, you could use array destructuring inside of a classic foreach() and make iterated compact() calls. (Demo)

$result = [];
foreach ($array as ['id' => $id, 'name' => $name]) {
    $result[] = compact(['id', 'name']);
}
var_export($result);

Amaro

Answer 3

If you want to edit the same array in place, you can simply iterate over them and unset them.

<?php 

$preserve_keys = ['id','name'];

foreach($arr as &$data){
    foreach($data as $key => $value){
        if(!in_array($key,$preserve_keys)){
            unset($data[$key]);
        }
    }
}

---

If you want it as a separate result, loop over and add it to the new array.

<?php

$new_result = [];

foreach($arr as $data){
    $new_result[] = [
        'id' => $data['id'],
        'name' => $data['name']
    ];
}

print_r($new_result);

Calandracalandria