Store multiple values in single key in json

Question

I need to store many values in single key of json. e.g.

{
  \"number\" : \"1\",\"2\",\"3\",
  \"alphabet\" : \"a\", \"b\", \"c\"
}

Somethin

Answer 1

{
  "number" : ["1","2","3"],
  "alphabet" : ["a", "b", "c"]
}