Python Booleans

A Boolean (named after the mathematician George Boole) is a special data type that has only two possible values:

True
False

These are not strings (they don’t have quotes around them) and they must be written with a capital T or capital F.

is_sunny = True
is_raining = False
print(is_sunny)   # True
print(is_raining) # False

Booleans are used for making decisions in your code, such as “Should I do this or not?”.

Comparison operators

Booleans often come from comparisons. Python checks something, and the result is either True or False.

Operator	Example	Result
`==`	`5 == 5`	True
`!=`	`5 != 3`	True
`<`	`2 < 7`	True
`<=`	`7 <= 7`	True
`>`	`10 > 3`	True
`>=`	`3 >= 4`	False

print(10 > 2)   # True
print(4 == 5)   # False

Try this

Print whether 15 is greater than 20.
Print whether 7 is equal to 7.
Print whether "apple" != "orange".

Boolean operators (and, or, not)

You can combine Booleans with logical operators:

and → True only if both sides are True
or → True if at least one side is True
not → flips True to False (and False to True)

print(True and False)  # False
print(True or False)   # True
print(not True)        # False

Example with numbers:

x = 10
print(x > 5 and x < 20)   # True (both conditions are True)
print(x < 5 or x == 10)   # True (second condition is True)
print(not (x == 10))      # False (because x == 10 is True, and not flips it)

Try this

Make age = 16. Print whether age is greater than 13 and less than 19.
Check if "dog" is equal to "cat" or "dog".
Use not to flip a True value into False.

Using Booleans in decisions (if statements)

Booleans are most powerful when combined with if statements to control what your program does.

is_hungry = True

if is_hungry:
    print("Time for a snack!")
else:
    print("Not hungry right now.")

You don’t need to write == True or == False. The Boolean itself is enough.

Try this

Ask the user their age.
Convert it to an integer.
Print "You are an adult" if they are 18 or over, otherwise print "You are a minor".

Converting to Booleans

You can convert values into Booleans with the bool() function.

print(bool(0))     # False
print(bool(1))     # True
print(bool(""))    # False (empty string)
print(bool("hi"))  # True (non-empty string)

Python treats some values as False: 0, 0.0, "" (empty string), None, and empty lists. Everything else is considered True.

Try this

Print bool(100).
Print bool("").
Print bool("Python").

Common beginner mistakes

Forgetting the capital letters: true and false don’t work — it must be True and False.
Thinking Booleans are strings: "True" is not the same as True.
Writing conditions like if is_sunny == True: when simply if is_sunny: is better.