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csv for reliable tabular text

The csv module is the reliable way to read and write CSV data in Python. It handles quoting, delimiters, and edge cases that are easy to get wrong with manual string splitting.

Why it is useful​

This is fragile:

line = 'alice,"New York, NY"'
print(line.split(","))

Quoted commas break simple parsing. csv handles that correctly.

Prefer the csv module​

import csv
from io import StringIO

text = 'name,city\nalice,"New York, NY"\n'
reader = csv.DictReader(StringIO(text))

for row in reader:
    print(row["city"])

Output:

New York, NY

Useful patterns​

  • csv.reader for simple row-based reading
  • csv.DictReader when named columns are clearer
  • csv.writer and csv.DictWriter for output

Rules of thumb​

  • Use csv, not split(","), for tabular text.
  • Prefer DictReader when column names matter.
  • Let the module handle quoting and delimiters for you.