Codeigniter - merge multiple associative array with condition - php

Question

I need to merge multiple arrays into one where a specific key & its value are same. Here is the Sample_Array1
array(n) {
[0]=> array {
["a"]=> "m1"
["b"]=> "x2"
}
[1]=> array {
["a"]=> "n1"
["b"]=> "y2"
} ....
Sample_Array2 with one common key & other different ones.
array(n) {
[0]=> array {
["b"]=> "x2"
["c"]=> "p1"
}
[1]=> array {
["b"]=> "x2"
["d"]=> "q1"
}
[2]=> array {
["b"]=> "y2"
["e"]=> "r1"
} ....
Need to merge / append Sample_Array2 to Sample_Array1 where key-"b" & its value are same. The expected output:
array(n) {
[0]=>
array(2) {
["a"]=> "m1"
["b"]=> "x2"
["c"]=> "p1"
["d"]=> "q1"
}
[1]=>
array(2) {
["a"]=> "n1"
["b"]=> "y2"
["e"]=> "r1"
} ....
I have tried so many similar questions but couldn't find the exact result.
PHP merge arrays with a condition The answer given on this link is not solving the purpose, its making different array for each new key, while I need to append the new keys in one array.

Answer 1

This should work, assuming you have the "b" index in all sub arrays.
$array1 = array();
$array1[] = array("a" => "m1", "b" => "x2", "c" => null);
$array1[] = array("a" => "n1", "b" => "y2");
$array2 = array();
$array2[] = array("b" => "x2", "c" => "p1");
$array2[] = array("a" => null, "b" => "x2", "d" => "q1");
$array2[] = array("b" => "y2", "e" => "r1");
function merge_on_key($array1, $array2, $key) {
$result_array = array();
foreach($array1 as $key1 => $sub_array1) {
$merged_array = array();
$sub_array1 = array_filter($sub_array1);
foreach($array2 as $key2 => $sub_array2) {
$sub_array2 = array_filter($sub_array2);
if($sub_array1[$key] == $sub_array2[$key]) {
$merged_array = array_merge($sub_array1, $sub_array2, $merged_array);
unset($array2[$key2]);
}
}
if (!empty($merged_array)) {
$result_array[] = $merged_array;
}
}
return array_merge($result_array, $array2);
}
$final_array = merge_on_key($array1, $array2, "b");
print_r($final_array);
In case you have to match the "b" index within the $array1 itself too, then simply use it twice:
$array1 = merge_on_key($array1, $array1, "b");
$final_array = merge_on_key($array1, $array2, "b");

Answer 2

i really have no idea what you want to achieve here - but based on your description the following code works
$arrA = [
0 =>
[
'a' => 'm1',
'b' => 'x2'
],
1 =>
[
'a' => 'n1',
'b' => 'y2'
]
];
$arrB = [
0 =>
[
'b' => 'x2',
'c' => 'p1',
],
1 =>
[
'b' => 'x2',
'd' => 'q1',
],
2 =>
[
'b' => 'y2',
'e' => 'r1',
],
];
foreach($arrB AS $arrData)
{
foreach($arrData AS $key => $val)
{
if ((isset($arrData['a']) && $arrData['a'] == $arrA[0]['a']) || (isset($arrData['b']) && $arrData['b'] == $arrA[0]['b']))
{
$arrA[0][$key] = $val;
}
elseif ((isset($arrData['b']) && $arrData['b'] == $arrA[1]['a']) || (isset($arrData['b']) && $arrData['b'] == $arrA[1]['b']))
{
$arrA[1][$key] = $val;
}
}
}
print_r($arrA);

Answer 3

Created the arrays similar to yours. $new_array is the resultant array that you are looking for.
$a=array();
$a[0]=array('a'=>'m1', 'b'=>'x2');
$a[1]=array('a'=>'n1', 'b'=>'y2');
$b=array();
$b[0]=array('b'=>'x2', 'c'=>'p1');
$b[1]=array('b'=>'x2', 'd'=>'q1');
$b[2]=array('b'=>'y2', 'e'=>'r1');
foreach($a as $row){
//echo '<pre>'; print_r($row);
foreach($b as $c=>$row1){
//echo '<pre>'; print_r($row1);echo $c;die;
if($row['b']==$row1['b']){
$new_array[]=array_merge($row, $row1);
}
}
}echo '<pre>'; print_r($new_array);

Answer 4

// Gather all values of b from both arrays
$all_b = array_unique(array_merge(array_column($arr1, 'b'), array_column($arr2, 'b')));
$res = [];
// For each b value
foreach($all_b as $b) {
$temp = [];
// Scan the arrays for items with the same b value
foreach($arr1 as $a1) {
if ($a1['b'] == $b) $temp = array_merge($temp, $a1);
}
foreach($arr2 as $a2) {
if ($a2['b'] == $b) $temp = array_merge($temp, $a2);
}
// Save them to new array
$res[] = $temp;
}
print_r($res);
demo on eval