Numbers

November 8, 2022

Python includes three numeric types such as integers int, float float, and complex complex numbers.

# an integer
a = 2

# a float
b = 3.89

# a complex number
c = 2 + 5j

Underscore

# use underscores to represent commas
>>> million = 1_000_000
>>> million
1000000

Round a number

# Round to a whole number
>>> round(1875.82)
1876

# Round to nearest tenth decimal place
>>> round(1875.82, 1)
1875.8

# Round to the nearest hundred
>>> round(1875.82, -2)
1900

# Round to the nearest thousand
>>> round(3256, -3)
3000

Compare floats

Due to floating-point representation error, use the isclose() function from the math module to compare floats. Otherwise, you may get confounding results when comparing numbers.

# This returns False due to floating point precision
>>> 0.1 + 0.2 == 0.3
False

# Using math.isclose() gives the expected result
>>> import math
>>> math.isclose(0.1 + 0.2, 0.3)
True

🐍 Pythonic Programming
by Gavin Wiggins © 2022