Basic Data Types in Python 3: Booleans

Posted by Kevin Whinnery on November 15, 2019.

Welcome back to our ongoing series of blog posts on basic data types in Python 3! Last time, we explored the functionality of strings. Today, we dive in to another key data type - booleans. Booleans (and "boolean logic") are an important concept in programming, representing the concept of "true" and "false".

If you're learning Python, you might also want to check out TwilioQuest 3. You'll learn about basic data types like the boolean, and much more about Python programming.

Ready to learn how to use booleans in Python 3? Let's get started!

Booleans in Python 3

Booleans are a concept that exists in every programming language. A boolean represents the idea of "true" or "false". When you are writing a program, there are often circumstances where you want to execute different code in different situations. Booleans enable our code to do just that.

You can declare a boolean value in your code using the keywords True and False (note the uppercase). The following code would create two boolean values and assign them to variables.

mullet_looks_good = False
python_is_fun = True

More commonly, a boolean value is returned as a result of some kind of comparison. The following code example would store a boolean value of False in the have_same_name variable after using the equality comparison operator, the == symbol.

my_name = "Wammu"
your_name = "Kars"

have_same_name = my_name == your_name

Boolean logic

Booleans are used in your code to make it behave differently based on current conditions within your program. You can use boolean values and comparisons in conjunction with the if, elif, and else keyoards as one means to achieve this.

my_age = 10

if my_age >= 100:
  print("One hundred years old! Very impressive.")
elif my_age <= 3:
  print("Awwww. Just a baby.")
else:
  print("Ah - a very fine age indeed")

In addition to testing for truth, you can also check if conditions are not true using the not keyword.

favorite_team = "Vikings"

if not favorite_team == "Vikings":
  print("Oh - how unfortunate.")
else:
  print("Skol, Vikings!")

More complex boolean logic

Sometimes you will need to evaluate multiple conditions in your boolean logic. For this purpose, you'll combine the and and or keywords. The and keyword compares two boolean values and returns True if both are true. The or keyword compares two values and returns True if any of the statements are true.

Let's look at an example. That uses the in keyword to see if a string is inside a list of values (we'll cover lists in a future article).

favs = ["Donatello", "Raphael"]

if "Michelangelo" in favs and "Donatello" in favs:
  print("Those are my favorite ninja turtles too!")
elif "Michelangelo" in favs or "Donatello" in favs:
  print("Well, one out of two isn't bad...")
else:
  print("Huh - not what I would have chosen.")

Wrapping up

Booleans are an important tool in any programming language. Using boolean logic, your code can react to data inside your program, and carry out different instructions under different circumstances. Hopefully, you've learned a bit about how to work with booleans in Python 3! Stay tuned for more blog posts in this series to learn more about basic data types like strings, numbers, booleans, lists, and dictionaries.

Also, be sure to download and play TwilioQuest 3 to learn even more about Python!


Matt Makai 2012-2019