Python – Convert CSV to JSON

Python – CSV to JSON

To convert CSV to JSON in Python, follow these steps.

1. Initialize a Python List.
2. Read the lines of CSV file using csv.DictReader() function.
3. Convert each line into a dictionary. Add the dictionary to the Python List created in step 1.
4. Convert the Python List to JSON String using json.dumps().
5. You may write the JSON String to a JSON file.

The format of CSV input and JSON output would be as shown in the following.

Input – data.csv

column_1,column_2,column_3
value_1_1,value_1_2,value_1_3
value_2_1,value_2_2,value_2_3
value_3_1,value_3_2,value_3_3

Output – data.json

[
    {
        "column_1": "value_1_1",
        "column_2": "value_1_2",
        "column_3": "value_1_3"
    },
    {
        "column_1": "value_2_1",
        "column_2": "value_2_2",
        "column_3": "value_2_3"
    },
    {
        "column_1": "value_3_1",
        "column_2": "value_3_2",
        "column_3": "value_3_3"
    }
]

Examples

1. Convert CSV file to JSON

In this example, we will read the following CSV file and convert it into JSON file.

data.csv – CSV File

a,b,c
25,84,com
41,52,org
58,79,io
93,21,co

import csv 
import json 

def csv_to_json(csvFilePath, jsonFilePath):
    jsonArray = []
      
    #read csv file
    with open(csvFilePath, encoding='utf-8') as csvf: 
        #load csv file data using csv library's dictionary reader
        csvReader = csv.DictReader(csvf) 

        #convert each csv row into python dict
        for row in csvReader: 
            #add this python dict to json array
            jsonArray.append(row)
  
    #convert python jsonArray to JSON String and write to file
    with open(jsonFilePath, 'w', encoding='utf-8') as jsonf: 
        jsonString = json.dumps(jsonArray, indent=4)
        jsonf.write(jsonString)
          
csvFilePath = r'data.csv'
jsonFilePath = r'data.json'
csv_to_json(csvFilePath, jsonFilePath)

data.json Output File

[
    {
        "a": "25",
        "b": "84",
        "c": "com"
    },
    {
        "a": "41",
        "b": "52",
        "c": "org"
    },
    {
        "a": "58",
        "b": "79",
        "c": "io"
    },
    {
        "a": "93",
        "b": "21",
        "c": "co"
    }
]

Summary

In this Python JSON Tutorial, we learned how to convert a CSV file to JSON file using csv and json libraries.