Difference between JSONObject and JSONArray

After having a short look at Google I found this link that describes the difference, yet from a syntax point of view.

When would one be preferred over the other in a programming scenario?


Solution 1:

When you are working with JSON data in Android, you would use JSONArray to parse JSON which starts with the array brackets. Arrays in JSON are used to organize a collection of related items (Which could be JSON objects).
For example: [{"name":"item 1"},{"name": "item2} ]

On the other hand, you would use JSONObject when dealing with JSON that begins with curly braces. A JSON object is typically used to contain key/value pairs related to one item. For example: {"name": "item1", "description":"a JSON object"}

Of course, JSON arrays and objects may be nested inside one another. One common example of this is an API which returns a JSON object containing some metadata alongside an array of the items matching your query:

{"startIndex": 0, "data": [{"name":"item 1"},{"name": "item2"} ]}

Solution 2:

The difference is the same as a (Hash)Map vs List.

JSONObject:

  • Contains named values (key->value pairs, tuples or whatever you want to call them)
    • like {ID : 1}
  • Order of elements is not important
    • a JSONObject of {id: 1, name: 'B'} is equal to {name: 'B', id: 1}.

JSONArray:

  • Contains only series values
    • like [1, 'value']
  • Order of values is important
    • array of [1,'value'] is not the same as ['value',1]

Example

JSON Object --> { "":""}

JSON Array --> [ , , , ]

{"employees":[
    {"firstName":"John", "lastName":"Doe"},
    {"firstName":"Anna", "lastName":"Smith"},
    {"firstName":"Peter", "lastName":"Jones"}
]}