Combine repeating elements as array in a multidimensional array - php

Question

I was wondering when working with multimedional arrays, if a certain key is the same, is there a way to combine the contents of other keys into its own array if a certain key is the same?
Something like this:
// name is the same in both arrays
array(
array(
'name' => 'Pepsi',
'store' => 'Over here',
'number' => '1234567'
),
array(
'name' => 'Pepsi',
'store' => 'Over here',
'number' => '5556734'
)
)
into something like this
array(
array(
'name' => 'Pepsi',
'store' => array('Over here', 'Over here'),
'number' => array('1234567', '5556734')
)
)
The defining key is checking if the name element is the same for the other arrays.

Answer 1

You can try a function like this.
function mergeByKey($array,$key){
$tmp_array = array();
foreach ( $array as $k => $row ) {
$merged = false;
foreach ($tmp_array as $k2 => $tmp_row){
if ($row[$key] == $tmp_row[$key]){
foreach ( $row as $k3 => $value ) {
if ($k3 == $key) continue;
$tmp_array[$k2][$k3][] = $value;
$merged = true;
}
}
if ($merged) break;
}
if (!$merged) {
$new_row = array();
foreach ( $row as $k4 => $value ) {
if ($k4 == $key) $new_row[$k4] = $value;
else $new_row[$k4] = array($value);
}
$tmp_array[] = $new_row;
}
}
foreach ( $tmp_array as $t => $row ) {
foreach ( $row as $t2 => $value ) {
if ( count($value) == 1 && $t2 != $key ) $tmp_array[$t][$t2] = $value[0];
}
}
return $tmp_array;
}
passing the array as first parameter and the key as second one.
I'm referencing to your array structure
edited: missed a piece
edited2: if resultin array contains elements with one string, it returns a string and not a array with one element
demo

Answer 2

This function uses a given field name as the grouping identifier and turns all other fields into arrays.
Note that single occurrences of your field name will yield arrays with a single element for the other fields. I wasn't sure whether that's a desirable trait, but just making sure you know ;-)
$arr = array(
array(
'name' => 'Pepsi',
'store' => 'Over here',
'number' => '1234567'
),
array(
'name' => 'Pepsi',
'store' => 'Over here',
'number' => '5556734'
)
);
function mergeArray($array, $column)
{
$res = array();
foreach ($array as $item) {
foreach ($item as $key => $value) {
if ($key === $column) {
$res[$column][$key] = $value;
} else {
$res[$column][$key][] = $value;
}
}
}
return array_values($res);
}
print_r(mergeArray($arr, 'name'));
Demo

Answer 3

Thanks to Gianni Lovece for her answer but I was able to develop a much simpler solution based on this problem. Just plug in the $result_arr to browse through and the $key you want to use as basis and it immediately outputs a multidimensional array with non-repeating values for repeating elements (see example below).
function multiarray_merge($result_arr, $key){
foreach($result_arr as $val){
$item = $val[$key];
foreach($val as $k=>$v){
$arr[$item][$k][] = $v;
}
}
// Combine unique entries into a single array
// and non-unique entries into a single element
foreach($arr as $key=>$val){
foreach($val as $k=>$v){
$field = array_unique($v);
if(count($field) == 1){
$field = array_values($field);
$field = $field[0];
$arr[$key][$k] = $field;
} else {
$arr[$key][$k] = $field;
}
}
}
return $arr;
}
For example, in the sample array for this question, running multiarray_merge($mysample, 'name') returns
array(
'Pepsi' => array(
'name' => 'Pepsi',
'store' => 'Over here', // String: Not an array since values are not unique
'number' => array('1234567', '5556734') // Array: Saved as array since values are unique
)
);