Parsing string to json in python

Parsing string to json in python

JSON (JavaScript Object Notation) is a text-based data format used for exchanging and storing data between web applications. It simplifies the data transmission process between different programming languages and platforms.

The JSON standard has become increasingly popular in recent years. It’s a simple and flexible way of representing data that can be easily understood and parsed by both humans and machines. JSON consists of key-value pairs enclosed in curly braces, separated by a colon.

Python provides various tools, libraries and methods for parsing and manipulating JSON data, making it a popular choice for data analysts, web developers, and data scientists.

In this guide, we’ll explore the syntax and data types of JSON, as well as the Python libraries and methods used for parsing JSON data, including more advanced options like JMESPath and ChompJS, which are very useful for web scraping data.

Reading JSON

One of the most common tasks when working with JSON data is to read its contents. Python provides several built-in libraries for reading JSON from files, APIs, and web applications. To read JSON data, you can use the built-in json module (JSON Encoder and Decoder) in Python.

The json module provides two methods, loads and load, that allow you to parse JSON strings and JSON files, respectively, to convert JSON into Python objects such as lists and dictionaries. Next is an example on how to convert JSON string to a Python object with the loads method.

import json json_input = ‘< "make": "Tesla", "model": "Model 3", "year": 2022, "color": "Red" >‘ json_data = json.loads(json_input) print(json_data) # Output:

Following, we display an example using the load method. Given a JSON file:

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Python JSON – How to Convert a String to JSON

Dionysia Lemonaki

In this tutorial you’ll learn the basics of JSON – what it is, where it is most commonly used, and its syntax.

You’ll also see how to convert a string to JSON in Python.

What is JSON?

JSON stands for JavaScript Object Notation.

It is a data format that’s used for storing and transferring information for web applications.

JSON was inspired by the JavaScript programming language, but it’s not tied to only one language.

Most modern programming languages have libraries for parsing and generating JSON data.

Where is JSON used?

JSON is mostly used for sending and receiving data between a server and a client, where the client is a webpage or web application.

It’s a much more solid format to use during the request-response cycle web applications use when connecting over a network. This is compared to the complicated and less compact XML, which was the format of choice years ago.

Basic JSON syntax

In JSON, data is written in key-value pairs, like so:

Data is enclosed in double quotation marks and the key-value pair is separated by a colon.

There can be more than one key-value pair and each one is separated by a comma:

"first_name": "Katie", "last_name": "Rodgers" 

The example above showed an object, a collection of multiple key-value pairs.

Objects are inside curly braces:

You can also create arrays, an ordered list of values, with JSON. In that case, arrays are contained inside square brackets:

[ < "first_name": "Katie", "last_name": "Rodgers" >, < "first_name": "Naomi", "last_name": "Green" >, ] // or: < "employee": [ < "first_name": "Katie", "last_name": "Rodgers" >, < "first_name": "Naomi", "last_name": "Green" >, ] > //this created an 'employee' object that has 2 records. // It defines the first name and last name of an employee 

How to work with JSON data in Python

Include the JSON module for Python

To use JSON with Python, you’ll first need to include the JSON module at the top of your Python file. This comes built-in to Python and is part of the standard library.

So, say you have a file named demo.py . At the top you would add the following line:

Use the json.loads() function

If you have JSON string data in your program like so:

#include json library import json #json string data employee_string = '' #check data type with type() method print(type(employee_string)) #output #

you can turn it into JSON in Python using the json.loads() function.

The json.loads() function accepts as input a valid string and converts it to a Python dictionary.

This process is called deserialization – the act of converting a string to an object.

#include json library import json #json string data employee_string = '' #check data type with type() method print(type(employee_string)) #convert string to object json_object = json.loads(employee_string) #check new data type print(type(json_object)) #output #

You can then access each individual item, like you would when using a Python dictionary:

#include json library import json #json string data employee_string = '' #check data type with type() method print(type(employee_string)) #convert string to object json_object = json.loads(employee_string) #check new data type print(type(json_object)) #output # #access first_name in dictionary print(json_object["first_name"]) #output #Michael 

Let’s take another example:

import json #json string employees_string = ''' < "employees": [ < "first_name": "Michael", "last_name": "Rodgers", "department": "Marketing" >, < "first_name": "Michelle", "last_name": "Williams", "department": "Engineering" >] > ''' #check data type using the type() method print(type(employees_string)) #output #

import json emoloyees_string = ''' < "employees" : [ < "first_name": "Michael", "last_name": "Rodgers", "department": "Marketing" >, < "first_name": "Michelle", "last_name": "Williams", "department": "Engineering" >] > ''' data = json.loads(employees_string) print(type(data)) #output #

import json employees_string = ''' < "employees" : [ < "first_name": "Michael", "last_name": "Rodgers", "department": "Marketing" >, < "first_name": "Michelle", "last_name": "Williams", "department": "Engineering" >] > ''' data = json.loads(employees_string) print(type(data)) #output # #access first_name for employee in data["employees"]: print(employee["first_name"]) #output #Michael #Michelle 

Conclusion

And there you have it – you now know the basics of using JSON in Python.

If you want to learn more about Python, freeCodeCamp has a Python Certification which takes you from the fundamentals such as variables, loops, and functions to more advanced concepts such as data structures. In the end you’ll also build 5 projects.

Thanks for reading and happy learning!

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String to JSON Python

JSON (JavaScript Object Notation) is a data format often used for sending and receiving data between servers and applications. Python provides an in-built package called json to handle data in JSON format. The two most important functions provided by this package are json.dumps() and json.loads() .

Introduction to JSON

Most of the applications today are divided into two domains:

Now, these two parts of an application need to communicate in some way. Therefore, we require a way to send data back and forth.

JSON (JavaScript Object Notation) is a popular and standardized format used for transmitting and receiving data between a server and an application or between two applications.

The following diagram shows the case of an application communicating with the server using data represented in JSON format:

A JSON object is very similar to a Python object. It also contains key-value pairs

For instance, the following is a JSON object:

This JSON object contains details about a person named «Thomas Shelby». It has the age, organisation, and a list of partner associated with this person.

You can notice similar types of values: string, numbers, lists, etc.

The following table shows the type conversion between Python and JSON:

Note that in a Python dictionary you can use a single or double quote to define the keys of a dictionary but in a JSON object you must use double quotes only.

• JSON is a standardized format used for transmitting and receiving data between a server and an application.

Converting a Python Dictionary to a JSON Object represented as a String

Python comes with a built-in package called json that we can import to use its function for handling JSON data.

The process of converting a Python dictionary into a JSON object is called serialization.

The term «serialization» refers to the transformation of data into a series of bytes to be stored on disk or transmitted across a network.

We will use the json.dumps function to convert a dictionary into a JSON object represented inside a string.

This function returns a JSON formatted string.

Explanation:

We created a Python dictionary with details of a person and passed it to the json.dumps function, this function will return a JSON version of the dictionary. We stored the returned JSON object in a variable and printed it.

• We can convert a Python dictionary into a JSON object using the dumps function from the json package.

Converting a JSON Object represented as a String to a Dictionary in Python

Now, let’s see how we can convert a JSON object available in a string to a Dictionary in Python.

The process of converting a JSON object into a Python dictionary is called deserialization.

Method 1: String Object to Dict Object Using json.loads

The json package also provides a function called json.loads for decoding a JSON object present in a string into a Python Dictionary.

Let’s see an example to get a clear understanding of the same.

Explanation:

We have a JSON object stored inside a string, we passed this string to the json.loads function. This function returned the equivalent Python dictionary. Then, we printed the dictionary.

Tip You can use the pprint package to pretty-print the dictionary in the previous example to make it more readable:

Method 2: str Object to dict Object using eval()

We can also convert a JSON string into a Python dictionary using the in-built eval function.

where expression is any valid Python code.

Explanation:

eval() allows us to evaluate arbitrary Python expressions from a string-based input. Here, we used it to parse a dictionary inside a string to an actual dictionary. Then, we printed the returned dictionary.

The function eval() is a lot versatile than the previously seen json.loads . It can be used to run any Python code and is not limited to converting a JSON string to a dictionary.

For instance, you can use eval() to perform calculations as follows:

• We can convert a JSON object into a Python dictionary using the loads function from the json package or using the eval function.

• JSON is a popular and standardized format used for transmitting and receiving data between a server and an application.
• A JSON object is similar to a Python dictionary containing key-value pairs.
• The process of converting a Python dictionary into a JSON object is called serialization.
  • We can convert a Python dictionary into a JSON object using the dumps function from the json package.
  • We can convert a JSON object into a Python dictionary using the loads function from the json package or using the eval function.

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