Group and merge array row data based on one column - php

Question

I have an array a bit like:
Array (
[1] => Array
(
[1] => 21
[2] => 3
[0] => Analyst
)
[2] => Array
(
[1] => 47
[2] => 8
[0] => Catalysis
)
[3] => Array
(
[1] => 1
[2] => 0
[0] => Biomaterials
)
[4] => Array
(
[3] => 12
[4] => 2
[0] => Analyst
)
[5] => Array
(
[5] => 12
[6] => 2
[0] => Analyst
)
...
However I would like to renumber those entries with the same [0] value so that I end up with
[1] => Array
(
[1] => 21
[2] => 3
[3] => 12
[4] => 2
[5] => 12
[6] => 2
[0] => Analyst
)
So far I've tried getting the [0] values out of the $results array by putting them in their own array and saying if you're already there then add [3] and [4] to where [1] and [2] are in a new array but it's not working.
$final = array();
$jArray = array();
foreach($results as $key => $result) {
if(!in_array($result[0],$jArray) && !empty($result[0])) {
$jArray[$i] = $result[0];
$i++;
}
}
for($x = 0; $x < count($results); $x++) {
$k = array_search($results[$x][0],$jArray);
if(!isset($results[$x][1]))
$final[$k][1] = $results[$x][1];
if(!isset($results[$x][2]))
$final[$k][2] = $results[$x][2];
if(!isset($results[$x][3]))
$final[$k][3] = $results[$x][3];
if(!isset($results[$x][4]))
$final[$k][4] = $results[$x][4];
if(!isset($results[$x][5]))
$final[$k][5] = $results[$x][5];
if(!isset($results[$x][6]))
$final[$k][6] = $results[$x][6];
}
Any simpler ways of doing this?

Answer 1

You can do this way...
$new_arr=array();
$arkeys = array_unique(array_map(function ($v){ return $v[0];},$arr));
foreach($arr as $k=>$arr1)
{
$new_arr[$arr1[0]][]=array_slice($arr1,0,count($arr1)-1);
}
foreach($arkeys as $v)
{
$new_arr[$v] = call_user_func_array('array_merge', $new_arr[$v]);
}
print_r($new_arr);
OUTPUT :
Array
(
[Analyst] => Array
(
[0] => 21
[1] => 3
[2] => 12
[3] => 2
[4] => 12
[5] => 2
)
[Catalysis] => Array
(
[0] => 47
[1] => 8
)
[Biomaterials] => Array
(
[0] => 1
[1] => 0
)
)
Working Demo

Answer 2

If you just want to group by the first element of the sub array, a single loop is enough:
$result = array();
foreach ($array as $sub_arr) {
$key = $sub_arr[0];
unset($sub_arr[0]);
if (!isset($result[$key])) {
$result[$key] = array();
}
$result[$key] += $sub_arr;
}

Answer 3

Here
$final = array();
foreach($results as $key => $result) {
if (!in_array($result[0], array_keys( $final ) ) && !empty($result[0])) {
$final[$result[0]] = array( $result[0] );
}
foreach($result as $k => $v) {
if ($k != 0 && isset($v)) {
$final[$result[0]][$k] = $v;
}
}
}