Standard Library Tour

The standard library is the toolbox that ships with Python. Four workhorses:

random — simulations and games

import random

roll = random.randint(1, 6)          # 1..6 inclusive
pick = random.choice(["a", "b", "c"])
random.seed(42)                      # reproducible "randomness"

seed pins the generator: same seed, same sequence — essential for tests and debugging.

datetime — timestamps and durations

from datetime import date

today = date(2026, 9, 13)
print(today.year, today.month)       # 2026 9
print(date(2026, 9, 13) - date(2026, 1, 1))   # 255 days, 0:00:00

statistics — one-line averages

import statistics

statistics.mean([2, 4, 9])   # 5
statistics.median([1, 9, 5]) # 5

The lesson here is bigger than any one module: before writing a helper, suspect the standard library already has it.