How To Open Two CSV Files In Python

Working with CSV files is a very common task when it comes to data manipulation and analysis. Often times, you may need to work with more than one CSV file and combine the data in those files for further processing. In this tutorial, we will learn how to open and read two CSV files in Python using the built-in csv module.

Step 1: Install Python and a Text Editor

Before we begin, make sure you have Python installed on your machine. If not, you can download it from the official Python website. Additionally, you’ll also need a text editor to write your code. Some recommended text editors are Visual Studio Code, Sublime Text, or Atom.

Step 2: Create Two CSV Files

First, let’s create two sample CSV files, file1.csv and file2.csv. Create these files in the same directory as your Python script.

For file1.csv, use the following content:

name,age,city
Alice,30,New York
Bob,25,Los Angeles
Charlie,22,San Francisco

For file2.csv, use the following content:

name,age,city
David,28,Boston
Eva,24,Chicago
Fiona,31,Seattle

Step 3: Opening the CSV Files in Python

To open the CSV files in Python, create a new Python script and import the csv module as shown below:

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import csv

Next, open both files in read mode using the open() function and the with statement. The with statement allows you to handle the files without worrying about closing them after usage.

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import csv
 
with open('file1.csv', mode='r') as f1, open('file2.csv', mode='r') as f2:
    # Code to read and process the CSV files comes here

Step 4: Reading the CSV Files Using the csv.reader Object

Now that we have both files opened, let’s read their content using the csv.reader object. By looping through the csv.reader object, we can access all the rows in each CSV file.

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import csv
 
with open('file1.csv', mode='r') as f1, open('file2.csv', mode='r') as f2:
    csv_reader1 = csv.reader(f1)
    csv_reader2 = csv.reader(f2)
 
    # Loop through the rows of file1.csv
    for row in csv_reader1:
        print(row)
 
    # Loop through the rows of file2.csv
    for row in csv_reader2:
        print(row)

This code will output the following:

['name', 'age', 'city']
['Alice', '30', 'New York']
['Bob', '25', 'Los Angeles']
['Charlie', '22', 'San Francisco']
['name', 'age', 'city']
['David', '28', 'Boston']
['Eva', '24', 'Chicago']
['Fiona', '31', 'Seattle']

Now you know how to open and read two CSV files using Python’s built-in csv module. You can further modify the code to combine or process the data as per your requirements.

Full Code

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import csv
 
with open('file1.csv', mode='r') as f1, open('file2.csv', mode='r') as f2:
    csv_reader1 = csv.reader(f1)
    csv_reader2 = csv.reader(f2)
 
    # Loop through the rows of file1.csv
    for row in csv_reader1:
        print(row)
 
    # Loop through the rows of file2.csv
    for row in csv_reader2:
        print(row)

Conclusion

In this tutorial, we learned how to open and read two CSV files in Python using the built-in csv module. By following these steps, you can easily work with multiple CSV files, manipulate their data, and use it for further data analysis or other tasks. Remember to always close your files or use the with statement to ensure proper file handling.