Compare Two Csv Files Using Python - GeeksforGeeks (2024)

We are given two files and our tasks is to compare two CSV files based on their differences in Python. In this article, we will see some generally used methods for comparing two CSV files and print differences.

Compare Two CSV Files for Differences in Python

Below are some of the ways by which we can compare two CSV files for differences in Python:

• Using Pandas library
• Using CSV module

file1.csv

Name,Age,CityJohn,25,New YorkEmily,30,Los AngelesMichael,40,Chicago

file2.csv

Name,Age,CityJohn,25,New YorkMichael,45,ChicagoEmma,35,San Francisco

Compare Two CSV Files Using Pandas library

In this approach, the Python Program loads both the CSV files (‘file1.csv’ & ‘file2.csv’) into two DataFrames. Once the CSV files are loaded, the compare() method provided by Pandas allows us to efficiently identify differences between the two DataFrames by comparing each corresponding row between the two DataFrames.

import pandas as pd# Read CSV filesdf1 = pd.read_csv('file1.csv')df2 = pd.read_csv('file2.csv')# Compare dataframesdiff = df1.compare(df2)# Print the differencesprint("Differences between file1 and file2:")print(diff)

Output

Differences between file1 and file2: Name Age City self other self other self other1 Emily Michael 30.0 45.0 Los Angeles Chicago2 Michael Emma 40.0 35.0 Chicago San Francisco

Compare Two CSV Files Using CSV Module

In this approach, the Python Program reads both the CSV files (‘file1.csv’ & ‘file2.csv’) using csv.reader function in reading mode. Then iterate over the rows of both CSV files and compare them.

import csv# Function to compare two CSV filesdef compare(file1, file2): differences = [] # Open both CSV files in read mode with open(file1, 'r') as csv_file1, open(file2, 'r') as csv_file2: reader1 = csv.reader(csv_file1) reader2 = csv.reader(csv_file2) # Iterate over rows in both files simultaneously for row1, row2 in zip(reader1, reader2): if row1 != row2: differences.append((row1, row2)) return differences# Define file pathsfile1 = 'file1.csv'file2 = 'file2.csv'# Call the compare_csv_files function and store the differencesdifferences = compare(file1, file2)for diff in differences: print(f"Difference found: {diff}")

Output

Difference found: (['Emily', '30', 'Los Angeles'], ['Michael', '45', 'Chicago'])Difference found: (['Michael', '40', 'Chicago'], ['Emma', '35', 'San Francisco'])