Python Booleans
Booleans represent one of two values:
True or
False.
In programming, you often need to know if an expression is True or False.
You can evaluate any expression in Python, and get one of two answers,
True or
False.
Boolean Values
When you compare two values, the expression is evaluated and Python returns the Boolean answer:
Example
When you run a condition in an
if statement,
Python returns
True or
False to
decide which block of code to execute.
Example: Print a message based on whether the condition is True or False
Evaluate Values and Variables
The
bool()
function allows you to evaluate any value, and gives you
True or
False in
return.
Example: Evaluate a string and a number
Most Values are True
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.
Example: The following will return True
Some Values are False
In fact, there are not many values that evaluate to
False, except
empty values, such as
(),
[],
{},
"", the
number 0, and
the value
None. And of
course the value
False
evaluates to
False.
Example: The following will return False
Functions can Return a Boolean
You can create functions that returns a Boolean Value.
Example: Print the answer of a function
Python also 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.
