PHP array diff different types - php

Question

I have 2 arrays of data from different data sources in different formats, but they represent the same resources. So id in one is the same as guid in the other for example.
Currently I am converting one of the arrays to match the other, and then running them via array_udiff to get the difference.
However, I need to compare 3 properties to check if they are a match, so I can't return -1,0,1 as the 3 fields either match, or do not match.
If I simply return -1 or 0, it works comparing $a to $b, but fails comparing $b to $a
$arr_a = [['id'=>1, 'a'=>1, 'b'=>0],['id'=>2, 'a'=>2, 'b'=>3],['id'=>3, 'a'=>1, 'b'=>0]];
$arr_b = [['id'=>3, 'a'=>1, 'b'=>0],['id'=>4, 'a'=>2, 'b'=>3],['id'=>5, 'a'=>1, 'b'=>0]];
function diff($a, $b) {
if( ($a['id'] == $b['id'])
&& ($a['a'] == $b['a'])
&& ($a['b'] == $b['b'])
) {
return 0;
} else {
return -1;
}
$not_in_b = array_udiff($arr_a, $arr_b,'diff');
$not_in_a = array_udiff($arr_b, $arr_a,'diff');
print_r($not_in_b);
print_r($not_in_a);
The above returns...
Array
(
[0] => Array
(
[id] => 1
[a] => 1
[b] => 0
)
[1] => Array
(
[id] => 2
[a] => 2
[b] => 3
)
)
Array
(
[0] => Array
(
[id] => 3
[a] => 1
[b] => 0
)
[1] => Array
(
[id] => 4
[a] => 2
[b] => 3
)
[2] => Array
(
[id] => 5
[a] => 1
[b] => 0
)
)
As you can see the diff of $a to $b works, but $b to $a does not...
How can I compare multiple vaules like this for equality...
UPDATE
This works, but making two arrays with the three identifying properties values as the keys...
$arr_a = [['id'=>1, 'a'=>1, 'b'=>0],['id'=>2, 'a'=>2, 'b'=>3],['id'=>3, 'a'=>1, 'b'=>0]];
$arr_b = [['id'=>3, 'a'=>1, 'b'=>0],['id'=>4, 'a'=>2, 'b'=>3],['id'=>5, 'a'=>1, 'b'=>0]];
$arra_a_keys=[];
foreach($arr_a as $item) {
$arra_a_keys[$item['id'].'_'.$item['a'].'_'.$item['b']] = $item;
}
$arra_b_keys=[];
foreach($arr_b as $item) {
$arra_b_keys[$item['id'].'_'.$item['a'].'_'.$item['b']] = $item;
}
$not_in_b = array_diff_key($arra_a_keys, $arra_b_keys);
$not_in_a = array_diff_key($arra_b_keys, $arra_a_keys);
print_r($not_in_b);
print_r($not_in_a);

Answer 1

To compare by ids only you can do the following:
$ids = array_column($a, 'id');
$guids = array_column($b, 'guid');
$not_in_b = array_filter($a, function ($item) use ($guids) {
return !in_array($item['id'], $guids);
});
$not_in_a = array_filter($b, function ($item) use ($ids) {
return !in_array($item['guid'], $ids);
});
Here is working demo.
Addition:
Also, you can do it with array_udiff:
$compareFunction = function ($a, $b) {
$id1 = isset($a['id']) ? $a['id'] : $a['guid'];
$id2 = isset($b['id']) ? $b['id'] : $b['guid'];
return strcmp($id1, $id2);
};
$not_in_b = array_udiff($a, $b, $compareFunction);
$not_in_a = array_udiff($b, $a, $compareFunction);
Here is working demo.
But be aware array_udiff is really not the most straight forward function. There is nothing about this in the documentation, but it not only compares but also sorts the arrays you provided with a callback function. That's why
The comparison function must return an integer less than, equal to, or
greater than zero if the first argument is considered to be
respectively less than, equal to, or greater than the second.
But this sorting also tricks the programmer, because he expected to that in function int callback ( mixed $a, mixed $b ) $a comes from $array1 and $b comes from $array2. That is not the case. You can read this article to find out more details. So I think that array_filter solution is more understandable

Answer 2

You could use a foreach for make array comparable
$ids1 = [];
foreach($a as $v1){
$i1[] = $v1['id'];
}
$ids2 = [];
foreach($b as $v2){
$i2[] = $v2['guid'];
}
$one_notin_two = array_diff($i1,$i2);
$two_notin_one = array_diff($i2,$i1);

Answer 3

You can solve this using array_column() and array_diff().
Here is sample code: See Live Demo
$a = [['id' => 1], ['id' => 2], ['id' => 3], ['id' => 4]];
$b = [['guid' => 3], ['guid' => 4], ['guid' => 6], ['guid' => 7]];
$a = array_column($a, 'id');
$b = array_column($b, 'guid');
$not_in_b = array_diff($a, $b);
$not_in_a = array_diff($b, $a);
Hope it should be solved your problem. Thank you.