How to read a CSV file in Python
Open the file with a with-block and use csv.reader for lists or csv.DictReader for dicts. Always pass encoding='utf-8'.
import csv
with open("data.csv", encoding="utf-8") as f:
reader = csv.DictReader(f)
for row in reader:
print(row["name"], row["age"])csv.DictReader reads the first row as headers and yields one dict per row, keyed by header name. This is safer than csv.reader (which yields plain lists) because column-order changes don't break your code.
The with-block guarantees the file is closed even if a row raises an exception. Always pass encoding='utf-8' explicitly — the platform default is Windows-1252 on Windows and utf-8 on macOS/Linux, which is a classic 'works on my machine' footgun.
For files over a few hundred MB, reach for pandas.read_csv() — it uses a C parser that's 5-10x faster.
Variations
csv.reader (lists, not dicts)
with open("data.csv", encoding="utf-8") as f:
for row in csv.reader(f):
print(row) # ['Alice', '30', 'Berlin']Use when the CSV has no header row.
Custom delimiter (TSV, pipe-separated)
with open("data.tsv", encoding="utf-8") as f:
reader = csv.reader(f, delimiter="\t")Also accepts quotechar= for non-standard quoting.
Large file → pandas
import pandas as pd
df = pd.read_csv("data.csv")Requires pip install pandas. 5-10x faster on files > 100MB.
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