Preserve keys array_splice from another array - php

Question

I am trying to keep keys from an array that i am counting and splicing trough array_splice function. There looks like that i am using wrong method to achieve my goal but i wanted to see if it's possible iwth array_splice
I have 2 arrays:
Task
Employees
Task and Employee (absent) array:
$task_id = ['998', '997', '996', '995', '995', '995', '995', '995', '995', '995', '995', '995'];
$absent = array(
[
'employee' => 'POL',
'absent_from' => '',
'absent_to' => ''
],
[
'employee' => 'FAR',
'absent_from' => '2021-07-12',
'absent_to' => '2021-07-16'
],
[
'employee' => 'FARs',
'absent_from' => '2021-07-12',
'absent_to' => '2021-07-16'
],
[
'employee' => 'FARss',
'absent_from' => '2021-07-12',
'absent_to' => '2021-07-16'
],
[
'employee' => 'FARsss',
'absent_from' => '2021-07-12',
'absent_to' => '2021-07-16'
],
);
What i am trying to achieve:
I want to delegate task_id equal to all employees. So for example i have 10 task and 10 employees i want to divide the tasks to 10 and delegate them to employees. If i have 9 task and 10 employees then everyone will get 2 task but one of them will only get 1 task.
First i add the names in another array from $absent array:
$absent_name = array();
foreach($absent as $key => $name) {
$absent_name[$key] = $name['employee'];
}
Then i try to splice the task_id among the employees (with counting the employees):
$output = array(); // Output / Result (Array)
$input = $task_id; // Tasks (ids)
$num_employees = count($absent_name); // number of employees
for (;$num_employees > 0; $num_employees -= 1) {
$output[] = array_splice($input, 0, ceil(count($input) / $num_employees));
}
print_r($output);
The result is this: (i have tested with more/less employees and task_id and looks like the result array is dividing just like i want it to but i want to keep the names not keys):
Array
(
[0] => Array
(
[0] => 998
[1] => 997
[2] => 996
)
[1] => Array
(
[0] => 995
[1] => 995
[2] => 995
)
[2] => Array
(
[0] => 995
[1] => 995
)
[3] => Array
(
[0] => 995
[1] => 995
)
[4] => Array
(
[0] => 995
[1] => 995
)
)
What i need:
Array
(
[POL] => Array
(
[0] => 998
[1] => 997
[2] => 996
)
[FAR] => Array
(
[0] => 995
[1] => 995
[2] => 995
)
[FARs] => Array
(
[0] => 995
[1] => 995
)
[FARss] => Array
(
[0] => 995
[1] => 995
)
[FARsss] => Array
(
[0] => 995
[1] => 995
)
)
or something simple just so i can add it easly in a DB:
Array
(
[POL] => [998,997,996]
)
[FAR] => [995,995,995]
)
etc......
)
Any idea if i need to change method or can i use array_splice?

Answer 1

I don't think array_splice is going to do any favors for you here, IMO you are working to hard, and should let PHP's array functions do most of the work for you. You can then concentrate on your business logic, which is pretty simple.
Use array_column to easily extract the emplyee IDs from the $absent array.
Use array_map to create and initialize an associative array of arrays, keyed by employee ID.
Loop through the task IDs and use the key, next, and reset functions to advance through the assignment map and wrap around as needed.
// Create an associative array keyed by the employee IDs
$employeeTaskMap = array_flip(array_column($absent, 'employee'));
// Initialize the values to empty arrays
$employeeTaskMap = array_map(fn() => [], $employeeTaskMap);
// Loop through the task IDs
foreach ($task_id as $currTaskId)
{
// Add the task ID to the array at the current pointer in the $employeeTaskMap
$employeeTaskMap[key($employeeTaskMap)][] = $currTaskId;
// Advance the array pointer, reset when we reach the end so we can wrap around
if (next($employeeTaskMap) === false)
{
reset($employeeTaskMap);
}
}
print_r($employeeTaskMap);
Output:
Array
(
[POL] => Array
(
[0] => 998
[1] => 995
[2] => 995
)
[FAR] => Array
(
[0] => 997
[1] => 995
[2] => 995
)
[FARs] => Array
(
[0] => 996
[1] => 995
)
[FARss] => Array
(
[0] => 995
[1] => 995
)
[FARsss] => Array
(
[0] => 995
[1] => 995
)
)
If you really want to use array_splice here for some reason and get your existing code working, use array_combine at the end to use the values of your employee names array as the keys for the output:
$taskBuffer = array(); // Output / Result (Array)
$input = $task_id; // Tasks (ids)
$num_employees = count($absent_name); // number of employees
for (; $num_employees > 0; $num_employees -= 1)
{
$taskBuffer[] = array_splice($input, 0, ceil(count($input) / $num_employees));
}
$output = array_combine($absent_name, $taskBuffer);
This works, but you are having to implement a lot of lower level logic that is unnecessary if you use a simpler, more declarative approach. That introduces more possibility for errors in your code, and makes it difficult for developers who may work with your code (including you six month from now) to understand what you are doing at a glance.