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What are arrays and objects in JSON?

JSON has two types of basic structures: arrays and objects.

What is an array?

An array is an ordered sequence of zero or more values enclosed in brackets [] and separated by commas.

An array of numbers:

[4, 6, 23.1, -4, 0, 56]

An array of strings:

["red", "green", "blue"]

Mixed array with a Boolean value and a null value:

[65, "toast", true, 21, null, 100]

What is an object?

An object is an unordered collection of zero or more name/value pairs enclosed in curly braces {} and separated by commas.

About objects

  • Objects are JSON's dictionaries, meaning they consist of keys and values, where you can look up a value with a given key.
  • Keys and values are separated from each other with a colon.
  • Key-value pairs are separated with commas.
  • Keys and values can be any data type, although strings are the most common.

An object in curly brackets that holds values for “red”, “green”, and “blue”.

{"red":205, "green":123, "blue":53}
  • The first key is the string "red", which has a value of 205.
  • Keys and values are separated by a colon.
  • Key-value pairs are separated with commas.

Data about a person:

{
   "firstName":"Manish",
   "lastName":"Patel",
   "employed":false
}
  • "firstName" = key; "Manish" = value (string)
  • "lastName" = key; "Patel" = value (string)
  • "employed" = key; false = value (Boolean)
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