Merge two 2d arrays and remove duplicate rows - php

Question

I searched a lot of SOF threads and no one seems to stick to my problem. What's kind of wired because this should be a well discussed question :)
Maybe I'm seeking for the wrong thing...
Scenario:
I have 2 arrays
$a = [
['id' => 5, 'name' => 'bruce'],
['id' => 7, 'name' => 'wayne']
];
// 2 elements
and
$b = [
['id' => 6, 'name' => 'chuck'],
['id' => 8, 'name' => 'norris'],
['id' => 7, 'name' => 'wayne'] //also exists in array $a
];
// 3 elements
My goal is
$c = [
['id' => 6, 'name' => 'chuck'],
['id' => 8, 'name' => 'norris'],
['id' => 7, 'name' => 'wayne'],
['id' => 5, 'name' => 'bruce']
];
// 4 elements (no duplicates)
I really don't care about the order inside the array(s) but I want to merge both into one, without having duplicates.
I tried array_merge and array_merge_recursive. No one works. Probably because the functions doesn't know the identifier which identifies each entry. Is there an easy solution or do I really have to create an own method/function for this?
Maybe there is a closure that I could use?

Answer 1

You can do this with very simple inbuilt function of PHP
$c = array_unique(array_merge($a,$b), SORT_REGULAR);
print_r( $c )
The output of the print_r is
Array
(
[0] => Array
(
[id] => 5
[name] => bruce
)
[1] => Array
(
[id] => 7
[name] => wayne
)
[2] => Array
(
[id] => 6
[name] => chuck
)
[3] => Array
(
[id] => 8
[name] => norris
)
)

Answer 2

$temp = array_merge($b, $a);
foreach ($temp as $v) {
$c[$v['id']] = $v;
}
If it finds the same id, the element will be overwritten in $c

Answer 3

Here's an approach at hashing each array with serialize after a key sort:
<?php
$a = [
['id' => 5, 'name' => 'bruce'],
['id' => 7, 'name' => 'wayne']
];
$b = [
['id' => 6, 'name' => 'chuck'],
['name' => 'wayne', 'id' => 7],
['id' => 8, 'name' => 'norris']
];
$merged = array_merge($a, $b);
foreach($merged as $k => $v) {
ksort($v);
$hashes[$k] = serialize($v);
}
$hashes = array_unique($hashes);
var_export(array_intersect_key($merged, $hashes));
Output:
array (
0 =>
array (
'id' => 5,
'name' => 'bruce',
),
1 =>
array (
'id' => 7,
'name' => 'wayne',
),
2 =>
array (
'id' => 6,
'name' => 'chuck',
),
4 =>
array (
'id' => 8,
'name' => 'norris',
),
)

Answer 4

If you index them on unique id then just add them. The result will be indexed on id which is convenient:
$result = array_column($a, null, 'id') + array_column($b, null, 'id');

Answer 5

I don't know how performant this is, but just using phps array-manipulation functions I get:
>>> array_values(array_merge(array_combine(array_column($a, 'name'), $a), array_combine(array_column($b, 'name'), $b)));
=> [
[
"id" => 5,
"name" => "bruce",
],
[
"id" => 7,
"name" => "wayne",
],
[
"id" => 6,
"name" => "chuck",
],
[
"id" => 8,
"name" => "norris",
],
]