Module 6

JSON

JavaScript Object Notation or simply called JSON is a very simple data structure. The primary compenents of this structure is “key: value” pairs house in objects or arrays or both.

Object

An object in JSON is indicated by {} and contains key:value pairs.

Array

An array in JSON is indicated by [] and it’s elements can be accessed by it’s index(elements start at zero).

Let’s use an exaple to demonstrate how to access parts of a JSON file.

indices.json
{
    "index": [
        {
            "zero": 0
        },
        {
            "one": 1
        },
        {
            "two": 2
        },
        {
            "three": 3
        }
    ],
    "letter": "a"
}
Get First Element
cat indices.json | jq '.["index"][0]'

In this example, index is an object with an array of values. We have accessed the first element of the array “zero”: 0

Get object letter
cat indices.json | jq '.["letter"]'

This will produce the value of object letter which is a

Working JSON data in VIM

Using the set paste command in VIM

../_images/setpaste1.png

Fig 1

What about when you use set paste and the formatting is still a mess? No worries, use this python command in VIM %!python -m json.tool

% - References current fiile name !python - Run python in shell calling module -m json.tool

../_images/json_tool.png

Fig 2

This modules focus is on parsing JSON data.