PYTHON PROGRAM • JSON, CSV & COLLECTIONS

Write and Read CSV Data in Python

Learn write and read csv data in python with a short, executable Python example.

Intermediatecsvreaderwriter

PROBLEM UNDERSTANDING

Input and expected output

Sample input

No input required

Sample output

[['name', 'mark'], ['Asha', '90']]

COMPLETE PYTHON PROGRAM

Complete Python implementation

import csv
with open('marks.csv', 'w', newline='', encoding='utf-8') as file:
    csv.writer(file).writerows([['name', 'mark'], ['Asha', 90]])
with open('marks.csv', newline='', encoding='utf-8') as file:
    print(list(csv.reader(file)))

CURRENT STEP

Select Start to walk through the important lines.

SELECTED LINE

No line selected

EXPECTED OUTPUT FOR THE SAMPLE

[['name', 'mark'], ['Asha', '90']]

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Import the required standard-library tools and prepare the sample data for write and read csv data.
Perform the file operation using csv and reader.
Display the result for write and read csv data and compare it with the documented sample output.

This example of write and read csv data computes the result directly from the prepared sample data. It demonstrates csv, reader, and writer and prints a deterministic result that can be checked against the sample output.

EFFICIENCY

Time and space complexity

Time complexity

O(n)

Auxiliary space

O(n)

DEBUGGING CHECKLIST

Common mistakes

Check this

For write and read csv data, keep the data shape and value types consistent with csv.

Check this

Keep every dependent statement inside the correct indented Python block.

Check this

Use the intended file mode and encoding, and let the context manager close the resource.

Try it yourself

Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.