How To Read Multiple Columns From CSV File In Python

In this tutorial, we will learn how to read multiple columns from a CSV file in Python. CSV (Comma Separated Values) is a simple file format that is widely supported by various applications, including Microsoft Excel and Google Sheets, to store and organize data. Python provides built-in support for reading and writing CSV files using the popular csv module.

Step 1: Preparing the CSV File

For this tutorial, let’s assume you have a sample CSV file named sample.csv with the following content:

Name,Age,Occupation,Salary
Alice,30,Software Developer,90000
Bob,35,Data Analyst,75000
Cathy,28,Web Developer,80000
David,45,Project Manager,120000

In this file, we have four columns: Name, Age, Occupation, and Salary.

Step 2: Importing the Required Libraries

To work with CSV files in Python, we will need to import the csv module. If you want to work with numerical data, you might also want to import the numpy module. In this tutorial, we will use only the csv module.

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import csv

Step 3: Reading the CSV File

To read a CSV file, we will use the csv.reader function. This function takes an iterable, such as a file object, and returns a reader object that iterates through the rows in the CSV file.

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with open('sample.csv', mode='r') as file:
    csv_reader = csv.reader(file, delimiter=',')
    for row in csv_reader:
        print(row)

The above code snippet will read and print the entire CSV file as a list of lists in this format:

['Name', 'Age', 'Occupation', 'Salary']
['Alice', '30', 'Software Developer', '90000']
['Bob', '35', 'Data Analyst', '75000']
['Cathy', '28', 'Web Developer', '80000']
['David', '45', 'Project Manager', '120000']

Step 4: Reading Multiple Columns from the CSV File

Now that we know how to read the entire CSV file, let’s read only specific columns. In this example, we will read Name and Occupation columns from the CSV file.

We can achieve this by accessing the indices of the desired columns in each row of the CSV file.

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with open('sample.csv', mode='r') as file:
    csv_reader = csv.reader(file, delimiter=',')
    next(csv_reader)  # Skipping the header row
 
    for row in csv_reader:
        name = row[0]
        occupation = row[2]
        print(name, occupation)

The above code snippet will only print the Name and Occupation columns from the CSV file:

Alice Software Developer
Bob Data Analyst
Cathy Web Developer
David Project Manager

Full Code

Here is the complete code for reading multiple columns from a CSV file:

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import csv
 
with open('sample.csv', mode='r') as file:
    csv_reader = csv.reader(file, delimiter=',')
    next(csv_reader)  # Skipping the header row
 
    for row in csv_reader:
        name = row[0]
        occupation = row[2]
        print(name, occupation)

Conclusion

In this tutorial, we learned how to read multiple columns from a CSV file in Python using the csv module. This is a simple and efficient method to process and manipulate data from a CSV file. You can now use this knowledge to read data from CSV files and perform further analysis, visualizations, or transformations using Python.