PHP : merge multiples arrays with common keys [duplicate] - php

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Merge two indexed arrays of indexed arrays based on first column value
(2 answers)
Closed 5 months ago.
I have 5 differents arrays in my script :
$array1 = array(
array( "id"=>"1", "title"=>"Batman" ),
array( "id"=>"2", "title"=>"Spiderman" ),
array( "id"=>"3", "title"=>"Titanic" ),
array( "id"=>"4", "title"=>"Dracula" ),
);
$array2 = array(
array( "id"=>"1", "releasedate"=>"1926" ),
array( "id"=>"2", "releasedate"=>"1956" ),
array( "id"=>"3", "releasedate"=>"2001" ),
array( "id"=>"4", "releasedate"=>"1982" ),
);
etc ...
As you see, info about movie number 1 is splitted on all the arrays (in fact -> 5 arrays). Then I would like to merge all my arrays to get something like this :
$array_FINAL = array(
array( "id"=>"1", "title"=>"Batman", "releasedate"=>"1926" ),
array( "id"=>"2", "title"=>"Spiderman", "releasedate"=>"1956" ),
array( "id"=>"3", "title"=>"Titanic", "releasedate"=>"2001" ),
array( "id"=>"4", "title"=>"Dracula", "releasedate"=>"1982" ),
);
I tried array_merge, array_combine, no good results. I also checked other topics on stackoverflow but no one help me (i may miss the one i need!)
Any help ? :)
EDIT : Sorry, i did would give a little more details ... rows in the arrays could be in misc. order, then according to my code example : the movie "Batman" can be in 1st row in the first array, but in the 3rd row in the second array...

Answer 1

If the order of both arrays is the same, you can simply use
$array_final = array_replace_recursive($array1, $array2);
However, if you want to merge them by the "id", you need to loop through them. A solution with the complexity O(m*n):
$array_final = array();
// loop through all movies in array1
foreach($array1 as $movie){
foreach($array2 as $movie_release) {
if ($movie['id'] == $movie_release['id']) {
$movie['releasedate'] = $movie_release['releasedate'];
break;
}
}
$array_final[] = $movie;
}
And a little less complex O(m+n):
// create arrays with the ID as key
$titles = array_column($array1, 'title', 'id');
$releasedates = array_column($array2, 'releasedate', 'id');
$array_final = array();
foreach($titles as $id => $title) {
$array_final[] = array(
'id' => $id,
'title' => $title,
'releasedate' => $releasedates[$id]
);
}

Answer 2

One of the solutions is:
$array1 = array(
array( "id"=>"1", "title"=>"Batman" ),
array( "id"=>"2", "title"=>"Spiderman" ),
array( "id"=>"3", "title"=>"Titanic" ),
array( "id"=>"4", "title"=>"Dracula" ),
);
$array2 = array(
array( "id"=>"1", "releasedate"=>"1926" ),
array( "id"=>"2", "releasedate"=>"1956" ),
array( "id"=>"3", "releasedate"=>"2001" ),
array( "id"=>"4", "releasedate"=>"1982" ),
);
// here we create pairs `id => releasedate`
$new_array2 = [];
foreach ($array2 as $v) {
$new_array2[$v['id']] = $v['releasedate'];
}
foreach ($array1 as &$value) {
// here we try to find key `$value['id']` in `$new_array2`
// and get it's value
if (isset($new_array2[$value['id']])) {
$value['releasedate'] = $new_array2[$value['id']];
}
}
If you're 100% sure that orders of ids are the same in both arrays you can just:
$i = 0;
foreach ($array1 as &$value) {
$value['releasedate'] = $array2[$i]['releasedate'];
$i++;
}

Answer 3

See this code prototype (it is simple and don't need to explanations I believe):
$fArr = [];
for ( $i = 1; $i <= 4; $i++ ) {
$fArr[] = [
'id' => $i,
'title' => $array1[$i - 1]['title'],
'releasedate' => $array2[$i - 1]['releasedate'],
];
}
Sandbox code example

Answer 4

Assuming all of your five arrays contain the id key, you can do this with a nested foreach loop.
foreach (array_merge($array1, $array2, $array3, $array4, $array5) as $item) {
foreach ($item as $key => $value) {
$result[$item['id']][$key] = $value;
}
}
The outer foreach iterates all the rows in all the arrays. The inner one loops over each column and assigns its value to the corresponding key in the result array.