Json library with Python to generate and read from Json string

Json (JavaScript Object Notation) is a text based data exchange format widely used in porting data to different languages and platforms. All most all programming languages have libraries to manage Json.

More details on PHP Json

import json
path="D:\\my_data\\student.json" # Json file path
f=open(path,'r')   # open in read mode
data=json.load(f) # data collected
for row in data:
    print(row)

Reading Json file from a link

import json
from urllib.request import urlopen

url = "https://www.plus2net.com/php_tutorial/student.json" # Json file path
f = urlopen(url)   # Open the URL
data = json.load(f) # Data collected

for row in data:
    print(row)

Output


{
    'id': 1, 
    'name': 'John Deo', 
    'class': 'Four', 
    'mark': 75, 
    'gender': 'female'
}

{
    'id': 2, 
    'name': 'Max Ruin', 
    'class': 'Three', 
    'mark': 85, 
    'gender': 'male'
}

{
    'id': 3, 
    'name': 'Arnold', 
    'class': 'Three', 
    'mark': 55, 
    'gender': 'male'
}

{
    'id': 4, 
    'name': 'Krish Star', 
    'class': 'Four', 
    'mark': 60, 
    'gender': 'female'
}

----
---

Here are some common methods used for managing Json strings.

Serializing JSON:

We can use a set of data in python and convert or encode them to Json string. Python objects in the form of of list, dictionary , string , integer etc can be converted by using dumps().

json.dumps() : to convert Python objects to Json string ( Serializing )
json.dump() : to convert Python object to Json to use along with file object.

Following Python objects can be converted to respective Json format.

Python	Json
Dictionary	Object
list, Tuple	Array
String , Unicode	String
int, long, float	Number
True	true
False	false
None	null

Deserializing

Data or string in the Json format can be decoded to get the objects in Python.

json.loads() : to convert Json data to Pyton Object ( Deserializing )
json.load() : converting Json data from file to Python object by using file object.
Here is a list of Json data which can be converted to Python objects.

Json	Python
Object	Dictionary
Array	List
string	Unicode
Number (int )	int , long
Number ( real )	float
true	True
false	False
null	None

MySQL Database records and Json format.

As the main requirement of Json is data exchange, here is the code to collect data from mysql table and then encode the same to get the data in Json format.

You can read more on MySQL connection and sqlalchemy here

from sqlalchemy import create_engine
engine = create_engine("mysql+mysqldb://userid:password@localhost/my_database")
my_connect = engine.connect()

import json

rs = my_connect.execute("SELECT * FROM student WHERE class='Three'")
my_data = rs.fetchall() # A list

j = json.dumps([dict(r) for r in my_data])

print(j)

my_connect.close()

Output

[{"id": 2, "name": "Max Ruin", "class": "Three", "mark": 85, "sex": "male"},
 {"id": 3, "name": "Arnold", "class": "Three", "mark": 55, "sex": "male"}, 
 {"id": 27, "name": "Big Nose", "class": "Three", "mark": 81, "sex": "female"}]

Creating a list by using data from JSON file

Here is the sample JSON file.

import json

path = "D:\\my_data\\student.json" # Use your sample file
fob = open(path,)
data = json.load(fob)

names = []
for student in data:
    # print(student['name'])
    names.append(student['name'])

print(names)
fob.close()

Using one line for loop in above code.

names=[r['name'] for r in data]

Pandas DataFrame and Json

to_json() : From DataFrame to Json
read_json() : From Json to DataFrame
Json data source for ttkbootstrap tableview
Json data viewer by using Tkinter Treeview : GUI application
Saving App settings in Json format by using Tkinter

All String methods Pandas read_json() Python- Tutorials

Subhendu Mohapatra

Author

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Json & Python