if Statement

Boolean conditions are used mostly in if statements to execute code conditionally. The code block following an if statement is only executed if the boolean expression evaluates to True.

if condition:
    CODE_BLOCK

Example:

def say_yes_please(condition):
    if condition:
        print("Computer says yes")


say_yes_please(True)
say_yes_please(False)
say_yes_please(1 > 2)
say_yes_please(None)  # None evaluates to False
say_yes_please("")  # Empty string evaluates to False
say_yes_please("some text")  # evaluates to True
say_yes_please([])  # Empty list evaluates to False
say_yes_please([1, 2, 3])  # evaluates to True

To check the boolean evaluation of an expression you can use the bool() function.

Python REPL

>>> bool("some text")
True
>>> bool([])
False