Encode Python objects as JSON strings, and decode JSON strings into Python objects

In Python, the json module provides an API similar to convert in-memory Python objects to a serialized representation known as JavaScript Object Notation (JSON) and vice-a-versa.

Encode Python objects as JSON strings

Basic Usage :

json.dump(obj, fp,
                  skipkeys=False,
                  ensure_ascii=True,
  		  check_circular=True,
		  allow_nan=True,
		  cls=None,
		  indent=None,
		  separators=None,
		  default=None,
		  sort_keys=False, **kw)

The above method serialize obj as a JSON formatted stream to fp (a .write()-supporting file-like object) using the following conversion table.

Options :

• The default value of skipkeys is False. If skipkeys is True, then dict keys that are not of a basic type (str, int, float, bool, None) will be skipped instead of raising a TypeError.
• The json module always produces str objects, not bytes objects. Therefore, fp.write() must support str input.
• If ensure_ascii is True (the default), the output is guaranteed to have all incoming non-ASCII characters escaped. If ensure_ascii is False, these characters will be output as-is.
• The default value of check_circular is True. If check_circular is False, then the circular reference check for container types will be skipped and a circular reference will result in an OverflowError.
• The default value of allow_nan is True. If allow_nan is False, then it will be a ValueError to serialize out of range float values (nan, inf, -inf) in strict compliance with the JSON specification, instead of using the JavaScript equivalents (NaN, Infinity, -Infinity).
• If indent is a non-negative integer or string, then JSON array elements and object members will be pretty-printed with that indent level. An indent level of 0, negative, or "" will only insert newlines. None (the default) selects the most compact representation. Using a positive integer indent indents that many spaces per level. If indent is a string (such as "\t"), that string is used to indent each level.
• Use (',', ': ') as default if indent is not None.
• The default value of sort_keys is False. If sort_keys is True, then the output of dictionaries will be sorted by key.

Examples : Python Dictionaries to JSON strings

Code :

import json
student = {"101":{"class":'V', "Name":'Rohit',  "Roll_no":7},
           "102":{"class":'V', "Name":'David',  "Roll_no":8},
           "103":{"class":'V', "Name":'Samiya', "Roll_no":12}}
print(json.dumps(student));

Output:

{"103": {"class": "V", "Name": "Samiya", "Roll_no": 12}, 
"102": {"class": "V", "Name": "David", "Roll_no": 8}, 
"101": {"class": "V", "Name": "Rohit", "Roll_no": 7}}

Examples : Python Dictionaries to JSON strings (sorted by key)

Code :

import json
student = {"101":{"class":'V', "Name":'Rohit',  "Roll_no":7},
           "102":{"class":'V', "Name":'David',  "Roll_no":8},
           "103":{"class":'V', "Name":'Samiya', "Roll_no":12}}
print(json.dumps(student, sort_keys=True));

Output:

{"101": {"Name": "Rohit", "Roll_no": 7, "class": "V"}, 
"102": {"Name": "David", "Roll_no": 8, "class": "V"}, 
"103": {"Name": "Samiya", "Roll_no": 12, "class": "V"}}

Examples : Python tuple to JSON array

Code :

import json
tup1 = 'Red', 'Black', 'White';
print(json.dumps(tup1));

Output:

["Red", "Black", "White"]

Examples : Python list to JSON array

Code :

import json
list1 = [5, 12, 13, 14];
print(json.dumps(list1));

Output :

[5, 12, 13, 14]

Examples : Python string to JSON string

Code :

import json
string1 = 'Python and JSON';
print(json.dumps(string1));

Output:

##################JSON AND REST ####################

import json

student = {"101":{"class":'V', "Name":'Rohit', "Roll_no":7},
"102":{"class":'V', "Name":'David', "Roll_no":8},
"103":{"class":'V', "Name":'Samiya', "Roll_no":12}}
#Encode
print(json.dumps(student));

#Encode
s=json.dumps(student)

# Decode
print(json.loads(s));

tup1 = ('Red', 'Black', 'White');
print(json.dumps(tup1));
#Encode
s=json.dumps(tup1)
#Decode
print(json.loads(s));

list1 = [5, 12, 13, 14];
print(json.dumps(list1));
#Encode
s=json.dumps(list1)
#Decode
print(json.loads(s));

string1 = 'Python and JSON';
print(json.dumps(string1));

#Encode
s=json.dumps(string1)
#Decode
print(json.loads(s));

x = True;
print(json.dumps(x));

s=json.dumps(x)
#Decode
print(json.loads(s));

x = -456;
y = -1.406;
z = 2.12e-10
print(json.dumps(x));
print(json.dumps(y));
print(json.dumps(z));

######################################

GET and POST  in web client and web server

#########################

pip install requests

REST FRAMEOWRK

https://medium.com/backticks-tildes/lets-build-an-api-with-django-rest-framework-32fcf40231e5

####################### JSON using local DJSNGO setup#########################

https://reqres.in/

>> import requests
>>> URL = "http://127.0.0.1:8000/student/"
>>> r = requests.get(url = URL, params = PARAMS)
>>> data=r.json()
>>> print(data)
[{'id': 1, 'name': 'a', 'mail': 'a@gmail.com', 'course': 'python', 'phonenumber': 87866788}, {'id': 2, 'name': 'b', 'mail': 'b@gmail.com', 'course': 'python', 'phonenumber': 44567767288}, {'id': 3, 'name': 'c', 'mail': 'c@gmail.com', 'course': 'Java', 'phonenumber': 9887667879}]
>>> print(data[0]['mail'])
a@gmail.com
>>>

#############

import requests
import json
d={}

d['a']={"name":"a","addr":"nizampet","course":"python"}

d['b']={"name":"b","addr":"kphb","course":"java"}

j=json.dumps(d,indent=2)
# Converts python data into json string
print(j)
print(type(j))
d=json.loads(j)
# Converts json string into python data
print(d)
print(type(d))

#################################

import requests
import json

# Posting name and age to url
f=open("rest_input.txt","r")
file_str=f.read()
data_json=json.loads(file_str)

#d={"name":"morpheus","job":"leader"}

r1 = requests.post(' https://reqres.in/api/users', data=data_json)
assert r1.status_code==201
print(r1.text)
print(r1.headers)
print(r1.json())
#
'{"name":"morpheus","job":"leader","id":"527","createdAt":"2018-11-28T08:12:22.189Z"}'

###########################