Python Booleans ☯️

True or False?

Booleans represent one of two values: True or False. In programming, you often need to know if an expression is True or False to make decisions.

💡 Analogy: The Light Switch

A Boolean is like a light switch. It can only be in one of two states: ON (True) or OFF (False). There is no "halfway" or "maybe".

✨ Evaluating Expressions

When you compare two values, the expression is evaluated and Python returns the Boolean answer:

python

print(10 > 9)   # True
print(10 == 9)  # False
print(10 < 9)   # False

✅ Truthy Values

Almost any value is evaluated to True if it has some sort of content.

Any string is True, except empty strings.
Any number is True, except 0.
Any list, tuple, set, and dictionary are True, except empty ones.

python

bool("abc")   # True
bool(123)     # True
bool(["apple"]) # True

❌ Falsy Values

There are not many values that evaluate to False, except empty values, such as (), [], , "", the number 0, and the value None.

python

bool(False)
bool(None)
bool(0)
bool("")
bool(())
bool([])
bool({})

🎯 Real-World Application: Feature Flags

Companies like Facebook use Booleans to turn features on or off for specific users.

python

is_dark_mode_enabled = True
if is_dark_mode_enabled:
    print("Applying dark theme...")
else:
    print("Applying light theme...")

🧠 Functions can Return a Boolean

You can create functions that return a Boolean Value:

python

def myFunction() :
  return True

if myFunction():
  print("YES!")
else:
  print("NO!")

💡 Did You Know? isinstance()

Python has many built-in functions that return a boolean value, like the isinstance() function, which can be used to determine if an object is of a certain data type:

python

x = 200
print(isinstance(x, int)) # True