CSV

A plain-text format for tabular data: one row per line, values separated by commas.

CSV (comma-separated values) is the lingua franca of spreadsheets and data exports. Each line is a row; commas separate the columns. Python’s built-in csv module reads and writes it safely — handling quoting and commas inside fields — and csv.DictReader gives each row as a dictionary keyed by column name.

Example 
import csv, io

text = "name,age\nAda,36\nBo,29\n"
rows = list(csv.DictReader(io.StringIO(text)))
print(rows[0]["name"], rows[0]["age"])
print(len(rows), "rows")
Output 
Ada 36
2 rows

Where this shows up in real Python

CSV is where data work often starts: exports from spreadsheets, reports, and simple datasets you clean or summarise.

Commonly used CSV tools

  • csv.reader(f) — read rows as lists
  • csv.DictReader(f) — read rows as dicts by header
  • csv.writer(f) — write rows
  • csv.DictWriter(f, fieldnames) — write dicts as rows
  • newline='' — open CSV files with this to avoid blank lines

Official documentation: Python Library Reference: csv

Related terms