how to convert to json from post in Yii2

Question

I want to create json from multiple selection from listbox in yii2 after post i receive following data

categorymodel[0]=11&categorymodel[1]=12&categorymodel[2]=13 

how to convert to json data and store in db.

json data like {"11","12","13"}

Answer 1

Once you have the proper array you can use eg:

$retJSON=  json_encode($categoryModel);