Lesson 3a - Numbers

Python has several “types” of data. We’ve worked with numbers a lot already, but there are also booleans, strings, and containers.

In this lesson, we’ll be working further with numbers. Python separates numbers into three categories: integers, floats, and complex numbers.

Lesson Objectives

• Use the type() function to see data types.
• Explore the differences between integers, floats, and complex numbers.

What Data Type Am I Working With?

The best way to see what type of data a variable is holding is by using the type() function.

apples = 25      # Integer
liters = 12.5    # Float (decimal)
q = 8.4 + 3j     # Complex Numbers

# We can use the print function to display the output of the type() function.
print(type(myVariable))
print(type(liters))
print(type(q))

<class 'int'>
<class 'float'> 
<class 'complex'>

Integers

Integers in Python, unlike other programming languages, don’t have a size limit. If you give Python enough memory resources, you could have 1000… with a million zeroes if you desired.

As we mentioned in a previous lesson, we can use math operations on integers. Addition (+), subtraction (-), multiplication (*), division (/), modulus (%), exponentiation (**), and floor division (//).

Division, regardless of whether it produces an integer value, turns the output into a float value.

Input

a = 6
b = 2
print(type(a))
print(type(b))

c = a / b       # This is 6/2, which should become 3 
print(c)
print(type(c))

Output

<class 'int'>
<class 'int'>
3.0
<class 'float'>

Despite it being 3, the output becomes 3.0, making it a float.

Floats

Floats refer to the real number set; integers and decimals. However, it’s important to note that floats are approximations (they’re only accurate to 7 decimal places). Floats are great for most use cases, but they shouldn’t be used when exact precision is required.

# This should add up to 1.0
0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1 + 0.1

0.9999999999999999

You can also use scientific notation for numbers.

G = 6.67430e-11
print(G)

g = 0.0000000000667430
print(g)

6.6743e-11
6.6743e-11

Complex Numbers

Python supports complex numbers, but they’re not often used.

# The imaginary number i is represented by the letter j in Python.
z = 3 + 1j

There are some interesting functions available for use with complex numbers that are supported by Python. If you’re interested, an in-depth tutorial on complex numbers can be found here.

Key Points / Summary

• You can use the type() function to inspect the data type of a variable.
• Floats are only approximations of decimal numbers and they can lead to rounding errors.
• Integers, floats, and complex numbers are the different number types Python supports.