Convert Text file to JSON in Python

Convert Text file to JSON in Python

In Python, converting a text file to JSON (JavaScript Object Notation) format is a common task for transmitting data between web applications and servers. Luckily, the process can be made easy with the help of the built-in json module. This module allows Python objects to be easily converted into their corresponding JSON objects, which can then be written to a file.

In this article, we will explore the various methods of converting text files to JSON in Python. We will begin by examining the basic process of converting a text file containing a single person’s details to a JSON file. Then, we will move on to more complex scenarios, such as when the text file contains multiple records. We will also discuss different parameters that can be used to improve the readability of the resulting JSON file. By the end of this article, you will have a comprehensive understanding of how to convert text files to JSON format in Python.

See the following table given below to see serializing JSON i.e. the process of encoding JSON.

Python object JSON object
dict object
list, tuple array
str string
int, long, float numbers
True true
False false
None null

To handle the data flow in a file, the JSON library in Python uses dump() function to convert the Python objects into their respective JSON object, so it makes easy to write data to files.



Various parameters can be passed to this method. They help in improving the readability of the JSON file. They are :

  • dict object : the dictionary which holds the key-value pairs.
  • indent : the indentation suitable for readability(a numerical value).
  • separator : How the objects must be separated from each other, how a value must be seperated from its key. The symbols like “, “, “:”, “;”, “.” are used
  • sort_keys : If set to true, then the keys are sorted in ascending order

Here the idea is to store the contents of the text as key-value pairs in the dictionary and then dump it into a JSON file. A simple example is explained below. The text file contains a single person’s details. The text1.txt file looks like:

The text file-sample1.txt

Now to convert this to JSON file the code below can be used:

# Python program to convert text
# file to JSON
import json
# the file to be converted to 
# json format
filename = 'data.txt'
# dictionary where the lines from
# text will be stored
dict1 = {}
# creating dictionary
with open(filename) as fh:
    for line in fh:
        # reads each line and trims of extra the spaces 
        # and gives only the valid words
        command, description = line.strip().split(None, 1)
        dict1[command] = description.strip()
# creating json file
# the JSON file is named as test1
out_file = open("test1.json", "w")
json.dump(dict1, out_file, indent = 4, sort_keys = False)

When the above code is executed, if a JSON file exists in the given name it is written to it, otherwise, a new file is created in the destination path and the contents are written to it.


The resultant JSON file:

Note the below line of code:

command, description = line.strip().split(None, 1)

Here split(None, 1) is used to trim off all excess spaces between a key-value pair and ‘1’ denotes split only once in a line. This ensures in a key-value pair, the spaces in the value are not removed and those words are not split. Only the key is separated from its value.

How to convert if multiple records are stored in the text file ?
Let us consider the following text file which is an employee record containing 4 rows.


The idea is to convert each employee’s detail into an intermediate dictionary and append that to one main resultant dictionary. For each intermediate dictionary a unique id is created and that serves as the key. Thus here the employee id and an intermediate dictionary make a key-value pair for the resultant dictionary to be dumped.

# Python program to convert text
# file to JSON
import json
# the file to be converted
filename = 'data.txt'
# resultant dictionary
dict1 = {}
# fields in the sample file 
fields =['name', 'designation', 'age', 'salary']
with open(filename) as fh:
    # count variable for employee id creation
    l = 1
    for line in fh:
        # reading line by line from the text file
        description = list( line.strip().split(None, 4))
        # for output see below
        # for automatic creation of id for each employee
        sno ='emp'+str(l)
        # loop variable
        i = 0
        # intermediate dictionary
        dict2 = {}
        while i<len(fields):
                # creating dictionary for each employee
                dict2[fields[i]]= description[i]
                i = i + 1
        # appending the record of each employee to
        # the main dictionary
        dict1[sno]= dict2
        l = l + 1
# creating json file        
out_file = open("test2.json", "w")
json.dump(dict1, out_file, indent = 4)

The attributes associated with each column is stored in a separate list called ‘fields’. In the above code, Each line is split on the basis of space and converted into a dictionary. Each time the line print(attributes) get executed, it appears as given below.

['Lisa', 'programmer', '34', '54000']
['Elis', 'Trainee', '24', '40000']
['Rickson', 'HR', '30', '47000']
['Kate', 'Manager', '54', '63000']

The JSON file created by this code looks like :


Convert nested text file to nested JSON:

If you have a nested text file that you want to convert to nested JSON, you can use the json module and some string manipulation functions in Python. Here’s an example code snippet:

import json

# the text file to be converted
filename = 'data.txt'

# read the text file and split it into sections
with open(filename, 'r') as textfile:
sections ='\n\n')

# convert each section to a dictionary and store it in a list
records = []
for section in sections:
# split the section into lines and remove extra whitespace
lines = [line.strip() for line in section.split('\n')]

# create a dictionary from the lines
record = {}
for line in lines:
key, value = line.split(':')
record[key.strip()] = value.strip()


# convert the list of dictionaries to a nested JSON object
jsonobj = json.dumps(records, indent=4)

# write the JSON object to a file
with open('data.json', 'w') as jsonfile:

In this example, the text file contains sections separated by two newline characters (\n\n). Each section represents a record with key-value pairs separated by a colon (:). The code reads the text file, splits it into sections, converts each section to a dictionary, and stores the dictionaries in a list. Finally, the list of dictionaries is converted to a nested JSON object and written to a file.

Last Updated on April 16, 2023 by admin

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