PHP Add null to array value if it doesn't exist - php

Question

I'm generating data arrays and want to add 0/null to a specific month, where no data is present, but been struggling with it for few days.
I'm generating the final dataset array like this
foreach ($patients as $key => $item) {
$labels[] = $item['month'];
usort($labels, "compare_months");
$labels = array_unique($labels);
$chartData[ $item['brand_name'] ]['data'][] =
$item['patientsCount'];
$chartData[ $item['brand_name'] ]['brand_data'] = [
"name" => $item['brand_name'],
"color" => $item['color']
];
}
foreach ($chartData as $item) {
$pointRadius++;
$dataSet[] = [
'label' => $item['brand_data']['name'],
'data' => $item['data'],
'pointRadius' => $pointRadius,
'fill' => false,
'borderWidth' => 1,
'backgroundColor' => "#" . $item['brand_data']['color'],
'borderColor' => "#" . $item['brand_data']['color'],
];
}
$finalData[] = [
'labels' => $labels,
'datasets' => $dataSet
];
Which gives me this json response
[
{
"labels":[
"April",
"May",
"June",
"July"
],
"datasets":[
{
"label":"Medicine 1",
"data":[
1
],
"pointRadius":1,
"fill":false,
"borderWidth":1,
"backgroundColor":"#ea5f2d",
"borderColor":"#ea5f2d"
},
{
"label":"Medicine 2",
"data":[
1,
1,
1
],
"pointRadius":2,
"fill":false,
"borderWidth":1,
"backgroundColor":"#ffb400",
"borderColor":"#ffb400"
},
{
"label":"Medicine 3",
"data":[
1,
1,
2
],
"pointRadius":3,
"fill":false,
"borderWidth":1,
"backgroundColor":"#ff7777",
"borderColor":"#ff7777"
},
{
"label":"Medicine 4",
"data":[
1,
1,
2
],
"pointRadius":4,
"fill":false,
"borderWidth":1,
"backgroundColor":"#64a36f",
"borderColor":"#64a36f"
},
{
"label":"Medicine 5",
"data":[
2
],
"pointRadius":5,
"fill":false,
"borderWidth":1,
"backgroundColor":"#e7e6fc",
"borderColor":"#e7e6fc"
}
]
}
]
As you can see, for some items, the data object only contains 1 value which is wrong, because I need to add zeros to months, where there is no data.
Can this be done in MySQL or is it better to use PHP and how?
EDIT 1
Here is the array I am currently getting.
Array
(
[MEDICINE 1] => Array
(
[April] => 1
)
[MEDICINE 2] => Array
(
[April] => 1
[July] => 2
)
[MEDICINE 3] => Array
(
[April] => 1
[May] => 1
[July] => 2
)
[MEDICINE 4] => Array
(
[May] => 1
[July] => 3
)
[MEDICINE 5] => Array
(
[June] => 2
)
[MEDICINE 6] => Array
(
[July] => 1
)
)
As you can see some medicines have data for only one month and I want to add these months to the medicine array with 0 value, if there is no data.

Answer 1

Add this line after each foreach: if (count($item['data']) < 2) continue;. Because you need skip if length of data is smaller than 2.
foreach ($patients as $key => $item) {
if (count($item['data']) < 2) continue;
$labels[] = $item['month'];
usort($labels, "compare_months");
$labels = array_unique($labels);
$chartData[ $item['brand_name'] ]['data'][] =
$item['patientsCount'];
$chartData[ $item['brand_name'] ]['brand_data'] = [
"name" => $item['brand_name'],
"color" => $item['color']
];
}
foreach ($chartData as $item) {
$pointRadius++;
if (count($item['data']) < 2) continue;
$dataSet[] = [
'label' => $item['brand_data']['name'],
'data' => $item['data'],
'pointRadius' => $pointRadius,
'fill' => false,
'borderWidth' => 1,
'backgroundColor' => "#" . $item['brand_data']['color'],
'borderColor' => "#" . $item['brand_data']['color'],
];
}
$finalData[] = [
'labels' => $labels,
'datasets' => $dataSet
];