JSON

• Open Standard widely used in Web APIs today.
• Purpose mainly for data serialization.
• Indentation is completely optional, except for with string literals.
• MAIN DATA STRUCTURES:
  • Objects/Dictionary
    • Groups of key value pairs.
    • Key must be a string.
    • Value can be objects, numbers, lists, boolean, strings or Null.
  • Lists
    • Ordered sequence of elements.
    • Elements can be same type as object values.
    • Can be objects, numbers, lists, boolean, strings or Null.

• Object/Dictionary ex.
  • Curly braces and double quotes encapsulate name:value pairs, separated by commas.
    • {“R10″:”4431”, “R20:”2921”, “R30″:3850”}

• List ex.
  • Same as Python
  • Encapsulated with square brackets and double quotes, separated by commas.
    • [“R1”, “R2”, “R3”]

• Multi-Line Notation – common, ultimately doesn’t matter because whitespaces do not matter.

• Using JSON in Python

import json

with open(“example.json”) as f:

data = f.read()

jsonDict = json.loads(data)

for k, v in jsonDict.items():

print( “The key {} uses a {} value.”.format(str(k), str(type(v))) )

• with open(“example.json”) as f:
  • With open for better exception handling and closes file when done.
• json.loads(data)
  • What converts imported string (with open <file>) into JSON object/dictionary.