how to parse the following php array - php

Question

I am trying to parse the following php array, somehow I am getting the result, but I couldn't get the expected output.
Array:
Array (
[0] => Array (
[countNos] => 2
[question_id] => 1
[question] => Is Service Best?
[rating] => 4
)
[1] => Array (
[countNos] => 1
[question_id] => 2
[question] => How much you benifitted?
[rating] => 5
)
[2] => Array (
[countNos] => 1
[question_id] => 2
[question] => How much you benifitted?
[rating] => 2
)
)
Current code:
foreach ($ratings as $rating) {
if (!in_array($rating['question_id'], $ratingArr)) {
$ratingArr[$rating['question_id']]['question_id'] = $rating['question_id'];
$ratingArr[$rating['question_id']]['question'] = $rating['question'];
}
for ($i = 5; $i >= 1; $i--) {
if (!in_array($rating['rating'], $ratingArr[$rating['question_id']]['stars'])) {
if ($i == $rating['rating']) {
$ratingArr[$rating['question_id']]['stars'][$i] = $rating['countNos'];
}
}
}
}
This is the output I am getting:
Notice: Undefined index: stars in C:\xampp\htdocs\mibs\module\Survey\src\Survey\Service\SurveyService.php on line 153
Warning: in_array() expects parameter 2 to be array, null given in C:\xampp\htdocs\mibs\module\Survey\src\Survey\Service\SurveyService.php on line 153
Array (
[1] => Array (
[question_id] => 1
[question] => Is Service Best?
[stars] => Array (
[4] => 2
)
)
[2] => Array (
[question_id] => 2
[question] => How much you benifitted?
[stars] => Array (
[5] => 1
[2] => 1
)
)
)
But I am expecting the following output:
Array(
[1] => Array(
[question_id] => 1
[question] => Is Service Best?
[stars] => Array(
[5] => 0
[4] => 2
[3] => 0
[2] => 0
[1] => 0
)
)
[2] => Array(
[question_id] => 2
[question] => How much you benifitted?
[stars] => Array(
[5] => 1
[4] => 0
[3] => 0
[2] => 1
[1] => 0
)
)
)
How can I parse this array, I am always having this type of issue, whenever I am parsing, how can I overcome this.

Answer 1

You're never creating a stars sub-array in $ratingArr when you initialize a new entry, that's causing the two warnings. To get all the zero entries, you should initialize this to an array of 5 zeroes. Then you don't need a loop to add the stars, you can just fill in the appropriate entry directly.
And you need to use array_key_exists, not in_array, to check whether there's already an entry for $rating['question_id'] in $ratingArr.
foreach ($ratings as $rating) {
if (!array_key_exists($rating['question_id'], $ratingArr)) {
$ratingArr[$rating['question_id']]['question_id'] = $rating['question_id'];
$ratingArr[$rating['question_id']]['question'] = $rating['question'];
$ratingArr[$rating['question_id']]['stars'] = array_fill(1, 5, 0);
}
$ratingArr[$rating['question_id']]['stars'][$rating['rating']] = $rating['countNos'];
}

Answer 2

Loop through your array and check if you already have a subArray with the question id in the result array. If not, initialize the subArray. And then just add the rating.
Code:
<?php
$result = [];
foreach($array as $v){
if(!isset($result[$v["question_id"]])){
$result[$v["question_id"]] = [
"question_id" => $v["question_id"],
"question" => $v["question"],
"stars" => array_fill_keys(range(5, 1), 0),
];
}
$result[$v["question_id"]]["stars"][$v["rating"]] += $v["countNos"]
}
?>