push first few elements of an array into 2d array - php

Question

Edit :
i Want a structure like this
'categories' => [
[
'name' => "science" ,
'questions' => [
[
'question' => 'C1_Q2',
'answer' => 'C1_A2',
],
[
'question' => 'C1_Q3',
'answer' => 'C1_A3',
]
]
]
but with help of loop
I am trying to create a questionnaire in which 3 steps need to be done
Create 3 arrays
1.categories - 2d -- like category["science"]["questions"]
2.questions
3.answers
step 1. add 10 questions in question array and add 10 answers in answer arrays
step 2.first 5 question of question array should be inserted to categories["science"]["questions"] and 5 answers to categories["science"]
["answers"]
I created Question and answer array and added 10 , 10 elements in it . but didnt succeed to add its elements as per step2 . I tried few logic
$Category=array();
$Q=array();
$A=array();
for($i=1;$i<=10;$i++)
{
$Q[] = "Question post".$i;
$A[] = "Answer post".$i;
//if($i==5)
//{
// array_push($Category,$Q[i]);
// break;
//} ---logic not working
}
//array first 5 Questions to category array
/*
for($i=1;$i<=5;$i++)
{
//$Category[]=$Q[i];
array_push($Category,$Q[i]);
}
*/ -- not working
print_r($Category);
Any suggestion or help would be appreciated

Answer 1

Try this:
$questions = [];
$answers = [];
for($i=1; $i <= 10; $i++) {
$questions[] = 'Question post' . $i;
$answers[] = 'Answer post' . $i;
}
$categories = ['science', 'something', 'else'];
$result = [];
foreach ($questions as $index => $question) {
if ($index % 5 != 0 || $index == 0) {
$category = current($categories);
} else {
$category = next($categories);
}
$result[$category][] = ['question' => $question, 'answer' => $answers[$index]];
}
var_dump($result);