Csv parse

Join & Split

syntax

separator.join(iterable)
str.split(separator)

example

words = ["Python", "is", "great"]
sentence = " ".join(words)
print(sentence)

csv_row = "alice,30,engineer"
fields = csv_row.split(",")
print(fields)

output

Python is great
['alice', '30', 'engineer']

Note split() with no arguments splits on any whitespace and removes empty strings. split(',') keeps empty strings between consecutive delimiters.

CSV Files

PY · File I/O

syntax

import csv

example

import csv

# Writing
with open("users.csv", "w", newline="", encoding="utf-8") as f:
    writer = csv.DictWriter(f, fieldnames=["name", "age"])
    writer.writeheader()
    writer.writerow({"name": "Alice", "age": 30})
    writer.writerow({"name": "Bob", "age": 25})

# Reading
with open("users.csv", newline="", encoding="utf-8") as f:
    for row in csv.DictReader(f):
        print(row["name"], row["age"])

output

Alice 30
Bob 25

Note Always pass newline='' when opening CSV files (the csv module handles line endings itself). DictReader/DictWriter are more readable than plain reader/writer.

PYPython