Hi There, In this post we’ll see how to work with CSV (Comma Separated Values) using Python.

In Programming we need to get information into and out of your programs to acomplich some specific tasks, Exchanging information through text files is a common way to share information between programs. One of the most popular formats for exchanging data is the CSV format.

What Is a CSV File?

CSV (Comma Separated Values) is a file format for data storage which looks like a text file. A comma-separated values (CSV) file is a delimited text file that uses a comma to separate values. A CSV file stores tabular data (numbers and text) in plain text. Each line of the file is a data record. Each record consists of one or more fields, separated by commas. The use of the comma as a field separator is the source of the name for this file format.

Here’s how does CSV structure looks like:

sample.csv

name, age, email
Mark, 25, mark@gmail.com
Robin, 26, robin@outlook.com
Sara, 27, sara@gmail.com

Notice how each piece of data is separated by a comma. Normally, the first line identifies each piece of data—in other words, the name of a data column. Every subsequent line after that is actual data

Importing the Requests Module

To work (Read/Write) with the CSV files in Python, First we must import the csv module. As csv is a built-in module for python we don’t need to install it. You can import csv simply by adding the following code at the beginning of your script:

import csv

Reading CSV File With Python

read_csv.py

# importing csv module
import csv

# reading csv file
with open('sample.csv', 'r') as csv_file:
    # creating a csv reader object
    read_csv = csv.reader(csv_file)

    # extracting field names through first row
    fields = next(read_csv)
    print(f'Column names are: {", ".join(fields)}')
    # extracting each row one by one
    for row in read_csv:
        print(f'Row details: {", ".join(row)}')

In the above code read_csv.py we are reading sample.csv and printing each row one by one by skipping the column headings row. The output for the above code will be as follows

output of read_csv.py

Column names are: name,  age,  email
Row details: Mark,  25,  mark@gmail.com
Row details: Robin,  26,  robin@outlook.com
Row details: Sara,  27,  sara@gmail.com

Writing CSV Files With Python

writer_csv.py

# importing csv module
import csv

#New list to add
new_line = ['Rob', '28', 'rob@hotmail.com']
# open file in appending mode
with open('sample.csv', 'a') as csv_file:
    # creating a csv writer object
    write_csv = csv.writer(csv_file, dialect='excel')
    # Appending the newlist to csv file
    write_csv.writerow(new_line)

In the above writer_csv.py we are writing a new list new_line = ['Rob', '28', 'rob@hotmail.com'] into sample.csv file.

CSV: