Control Flow & Loops

Making Decisions with if

Control flow allows your program to react differently based on conditions.

score = 85

if score >= 90:
    grade = "A"
elif score >= 80:
    grade = "B"
else:
    grade = "C"

Truthy & Falsy Values

In Python, empty containers and zeros evaluate to False:

data = []
if not data:
    print("Data is empty!") # This will run