Processing CSV Data with the csv Module

Reading CSV

csv_read.py

import csv
 
with open("input.csv", newline="", encoding="utf-8") as f:
    reader = csv.DictReader(f)
    for row in reader:
        print(row)

Writing CSV

csv_write.py

import csv
 
rows = [
    {"name": "Alice", "score": 95},
    {"name": "Bob", "score": 88},
]
 
with open("out.csv", "w", newline="", encoding="utf-8") as f:
    writer = csv.DictWriter(f, fieldnames=["name", "score"])
    writer.writeheader()
    writer.writerows(rows)

Common cleanup

• strip whitespace
• handle missing values
• normalize casing

🧪 Try It Yourself

Exercise 1 – List Files with os.listdir

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Exercise 2 – Join Paths with os.path.join

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Exercise 3 – Write and Read a File

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