How to merge two JSON under an Array in PHP - php

Question

I get details from the user through HTML form, and onclick the form submission, I run the php file, save2json.php, which retrieves from HTML form, and posts it as JSON in the file appointments.json.
save2json.php
$formdata = array(
$_POST['doctor'] => array(
'name'=> $_POST['name'],
'phone'=> $_POST['phone'],
'bday'=> $_POST['bday'],
'datepicker'=> $_POST['datepicker'],
)
);
$filetxt = 'appointments.json';
$arr_data = array();
if(file_exists($filetxt))
{
$jsondata = file_get_contents($filetxt);
$arr_data = json_decode($jsondata, true);
}
$arr_data[] = $formdata;
$jsondata = json_encode($arr_data, JSON_PRETTY_PRINT);
if(file_put_contents('appointments.json', $jsondata))
What I get: [appointments.json]
[{
"Doctor #3": {
"name": "0",
"phone": "0",
"bday": "0",
"datepicker": "0"
}
}, {
"Doctor #3": {
"name": "1",
"phone": "1",
"bday": "1",
"datepicker": "1"
}
}, {
"Doctor #1": {
"name": "2",
"phone": "2",
"bday": "2",
"datepicker": "2"
}
}, {
"Doctor #2": {
"name": "3",
"phone": "3",
"bday": "3",
"datepicker": "3"
}
}]
What I want: [appointments.json]
[{
"Doctor #3": [{
"name": "0",
"phone": "0",
"bday": "0",
"datepicker": "0"
},
{
"name": "1",
"phone": "1",
"bday": "1",
"datepicker": "1"
}
],
"Doctor #1": {
"name": "2",
"phone": "2",
"bday": "2",
"datepicker": "2"
},
"Doctor #2": {
"name": "3",
"phone": "3",
"bday": "3",
"datepicker": "3"
}
}]
If it is under same doctor, I want to make both objects come under the same array. And if it isn't like Doctor 1 and Doctor 2, in this case, I want them as separate apart from Doctor 3 array.
Thanks in Advance :)

Answer 1

This is the first attempt to put it inside the doctor array key:
<?php
// build the array
$docDetails = array(
'name'=> $_POST['name'],
'phone'=> $_POST['phone'],
'bday'=> $_POST['bday'],
'datepicker'=> $_POST['datepicker'],
);
// get the file's content as an array.
$filetxt = 'appointments.json';
if(file_exists($filetxt))
$arr_data = json_decode(file_get_contents($filetxt), true);
else
$arr_data = array();
$arr_data[$_POST['doctor']][] = $docDetails;
?>