Standard Python Modules

A few of Python's built-in modules that ship with the language itself — no installation needed, just an import.

Math Module

Extra math functions beyond Python's built-in operators — import it first with import math.

import math

print(math.sqrt(144))
print(math.ceil(4.1))
print(math.floor(4.9))
print(math.factorial(5))
print(math.pi)
12.0 5 4 120 3.141592653589793

sqrt() finds a square root, ceil()/floor() round up or down to the nearest whole number, factorial() computes n!, and pi is a ready-made constant for π.

Random Module

Generates pseudo-random numbers and choices — import it with import random.

import random

print(random.random())
print(random.randint(1, 10))
print(random.choice(["a", "b", "c"]))

nums = [1, 2, 3, 4]
random.shuffle(nums)
print(nums)
0.7334125841448089 7 b [3, 1, 4, 2]

random() gives a float between 0 and 1, randint(a, b) gives a whole number between a and b inclusive, choice() picks one item from a sequence, and shuffle() rearranges a list in place. Since these are random, running the same code again will give different results.

Statistics Module

Common statistical calculations on a set of numbers — import it with import statistics.

import statistics

data = [4, 8, 15, 16, 23, 42]
print(statistics.mean(data))
print(statistics.median(data))
print(statistics.mode([1, 1, 2, 3]))
18 15.5 1

mean() gives the average, median() gives the middle value once sorted (averaging the two middle values when there's an even count), and mode() gives whichever value appears most often.