NB: Numbers

Programming for Data Science

Built-in Functions

Python has many built-in mathematical functions for numbers.

\(2\) raised to \(3 = 8\)

pow(2,3)

Returns \(2\), the absolute value of its argument.

abs(-2)

Rounding up or down its argument (to closest whole number).

Rounds up to \(3.0\).

round(2.8)

Rounds down to \(1.0\).

round(1.1)

You can specify how many decimal places to round to as well.

round(5.36958211, 2)

5.37

Python’s Math library contains many other functions to perform mathematical operations.

See the Python docs on the math library for more information.

First, we import the library like so:

import math

We’ll learn more about importing libraries into your programs later in the course.

math.sqrt(12)

3.4641016151377544

print(math.floor(2.5)) # returns largest whole number less than the argument
print(math.floor(2.9))
print(math.floor(2.1))

2
2
2

math.log(100, 10)

2.0

math.log(256, 2)

8.0

Python has a library to help you generate random numbers.

Random number generators are an essential part of any data scientist’s toolkit.

import random

Using random() will return a number between \(0\) and \(1\).

print(random.random())

0.605894272418689

We may specify a range in the parentheses.

This will return a random integer in the range \(1\) to \(100\) inclusive.

print(random.randint(1,100))