PHP json_encode() specific key of an array - php

Question

I am using PHP 5.5.12.
I have an array like:
Array
(
[0] => Array
(
[user_id] => 3
[medicine_id] => 1
[time] => Array
(
[0] => stdClass Object
(
[event_type] => before_breakfast
[time] => 07:00:00
)
[1] => stdClass Object
(
[event_type] => after_breakfast
[time] => 07:30:00
)
)
)
[1] => Array
(
[user_id] => 3
[medicine_id] => 2
[time] => Array
(
[0] => stdClass Object
(
[event_type] => before_lunch
[time] => 13:00:00
)
[1] => stdClass Object
(
[event_type] => after_lunch
[time] => 14:00:00
)
)
)
[2] => Array
(
[user_id] => 3
[medicine_id] => 3
[time] => Array
(
[0] => stdClass Object
(
[event_type] => before_dinner
[time] => 20:00:00
)
[1] => stdClass Object
(
[event_type] => after_lunch
[time] => 21:00:00
)
)
)
)
I want to json_encode() the field time of each root level.
I tried using:
foreach ($user_medicine_times as $user_medicine_key => $user_medicine_value) {
$user_medicine_value['time'] = json_encode($user_medicine_value['time'], true);
}
and:
foreach ($user_medicine_times as $user_medicine_key => &$user_medicine_value) {
$user_medicine_value['time'] = json_encode($user_medicine_value['time'], true);
}
But using print_r($user_medicine_value), it returns the same array.
I want the result to be as follows:
Array
(
[0] => Array
(
[user_id] => 3
[medicine_id] => 1
[time] => "[{"event_type":"before_breakfast","time":"07:00:00"},{"event_type":"after_breakfast","time":"07:30:00"}]"
)
[1] => Array
(
[user_id] => 3
[medicine_id] => 2
[time] => "[{"event_type":"before_lunch","time":"13:00:00"},{"event_type":"after_lunch","time":"17:00:00"}]"
)
[2] => Array
(
[user_id] => 3
[medicine_id] => 3
[time] => "[{"event_type":"before_dinner","time":"20:00:00"},{"event_type":"after_lunch","time":"17:00:00"}]"
)
)
How can I achieve this result?

Answer 1

I have read your question earlier and prepared the answer but you removed it before i paste the answer. Anyways here is the solution
function outer(&$val, $key) {
$val['time'] = json_encode($val['time']);
}
array_walk($your_array, 'outer');
print_r($your_array);

Answer 2

You can replace your foreach loop's content with something like this:
foreach ($user_medicine_times as $user_medicine_key => $user_medicine_value) {
$user_medicine_times[$user_medicine_key]['time'] = json_encode($user_medicine_value['time'], true);
}

Answer 3

Maybe the json encode fails because your time array contains an stdClass Object. Try to convert this like that :
$result = array();
foreach ($user_medicine_value['time'] as $value) {
$result['event_type'] = $value->event_type;
$result['time'] = $value->time;
}
$user_medicine_value['time'] = $result;

Answer 4

Because, in every iteration, the value is not being saved anywhere,
You have two options here, either make new array having time key with json_encode() or pass the value by reference as shown below.
foreach ($user_medicine_times as $user_medicine_key => &$user_medicine_value) {
^
$user_medicine_value['time'] = json_encode($user_medicine_value['time'], true);
}