Merge multidimentional array if parent id same then merge child data - php

Question

I want to convert below array.
Criteria is,
If projectId same then store same project id data under array of project which contains projectId as key.
Array
(
[0] => Array
(
[PMST] => Array
(
[id] => 4
[project_id] => 25
[task_name] => Final task 3
[start_date] => 2016-06-21 00:00:00
[end_date] => 2016-06-29 00:00:00
)
[PMSP] => Array
(
[id] => 25
[project_name] => Project 3
[start_date] => 2016-06-01 00:00:00
[end_date] => 2016-06-04 00:00:00
)
)
[1] => Array
(
[PMST] => Array
(
[id] => 9
[project_id] => 28
[task_name] => Task Test 333 edit
[start_date] => 2016-06-19 00:00:00
[end_date] => 2016-06-29 00:00:00
)
[PMSP] => Array
(
[id] => 28
[project_name] => Project Employee Test
[start_date] => 2016-06-10 00:00:00
[end_date] => 2016-06-30 00:00:00
)
)
[2] => Array
(
[PMST] => Array
(
[id] => 1
[project_id] => 28
[task_name] => Task 1
[start_date] => 2016-06-01 00:00:00
[end_date] => 2016-06-04 00:00:00
)
[PMSP] => Array
(
[id] => 28
[project_name] => Project Employee Test
[start_date] => 2016-06-10 00:00:00
[end_date] => 2016-06-30 00:00:00
)
)
)
Desire Output
Array
(
[25] => Array
(
[PMSP] => Array
(
[id] => 25
[company_id] => 1114701
[project_name] => Project 3
[start_date] => 2016-06-01 00:00:00
[end_date] => 2016-06-04 00:00:00
)
[taskdetails] => Array
(
[0] => Array(
[PMST] => Array
(
[id] => 4
[project_id] => 25
[company_id] => 1114701
[task_name] => Final task 3
[start_date] => 2016-06-21 00:00:00
[end_date] => 2016-06-29 00:00:00
)
)
)
)
[28] => Array
(
[PMSP] => Array
(
[id] => 28
[company_id] => 1114701
[project_name] => Project Employee Test
[start_date] => 2016-06-10 00:00:00
[end_date] => 2016-06-30 00:00:00
)
[taskdetails] => Array
(
[0] => Array
(
[PMST] => Array
(
[id] => 9
[project_id] => 28
[company_id] => 1114701
[task_name] => Task Test 333 edit
[start_date] => 2016-06-19 00:00:00
[end_date] => 2016-06-29 00:00:00
)
)
[1] => Array(
[PMST] => Array
(
[id] => 1
[project_id] => 28
[company_id] => 1114701
[task_name] => Task 1
[start_date] => 2016-06-01 00:00:00
[end_date] => 2016-06-04 00:00:00
)
)
)
)
)

Answer 1

Loop over your input array using foreach, adding the PMST data to an output array as you go. It looks like it's safe to assume the PMSP data for two tasks on the same project will be the same.
$output = [];
foreach ($input as $task) {
if (!isset($output[$task["PMSP"]["id"]])) {
$output[$task["PMSP"]["id"]] = ["PMSP" => $task["PMSP"], "taskdetails" => []];
}
$output[$task["PMSP"]["id"]]["taskdetails"][] = $task["PMST"];
}

Answer 2

See the below example
Example
$data = [];
foreach ($a as $b) {
$key = $b["PMSP"]["id"];
if (!isset($data[$key])) {
$data[$key] = ["PMSP" => $b["PMSP"], "taskdetails" => []];
}
$data[$key]["taskdetails"][] = $b["PMST"];
}
echo "<pre>";
print_r($data);exit();
Your latest data
Example 2