Read and Write JSON in Python

What is a JSON file?

According to Wikipedia JSON is “JavaScript Object Notation (JSON, pronounced /ˈdʒeɪsən/; also /ˈdʒeɪˌsɒn/) is an open standard file format, and data interchange format, that uses human-readable text to store and transmit data objects consisting of attribute–value pairs and array data types (or any other serializable value).”

In Short JSON is:

• It is Light-weight file format to exchange data.
• Data is written in key : value pairs. just like dictionaries in python.

Read JSON

Luckily Python has an in-built package named ‘JSON’ which can parse and manipulate data.

import json  #imports json package

To parse the json file we need open the json file in python and then pass the file object in json.load() function.

JSON file :

import json
f=open("summary.json",'r')
 #open json as file object
data=json.load(f)  #parse file object 
print(data)
 #print parsed json

Next, we want to access the key: vale pairs in the json file.

Just like dictionaries in python, data can be accessed by using indexing where ‘key’ is index value.Remember Keys are case sensitive.

import json
f=open("summary.json",'r')
 #covid-19 data 16aug2020
data=json.load(f)
print(data['Global'])  #print value in 'Global' key.
print(data['Global']['NewConfirmed']) #print integer value in new confirmed
f.close()

Write JSON

As we have already seen that JSON is very much similar to python dictionaries therefore the simplest way to create a JSON file would be to convert dictionary into JSON.

Json dump function does the job of json creation easily.

import json
data={
	"person":{
				"name":"Rajesh",
				"age":"23",
				"gender":"M",
				"height":"5.5ft"
	},

}
 #make a dictionary with key-value pairs
with open('datadump.json', 'w') as json_file: #open file to write
    json.dump(data, json_file)  #dump json data