Conditional Statements

if, elif, else — controlling the flow of your programs with conditionals.

The if Statement

Conditional statements allow your program to make decisions. Python uses indentation (4 spaces) to define code blocks — there are no curly braces.

temperature = 28

if temperature > 30:
    print("It's hot outside.")
elif temperature > 20:
    print("Nice and warm.")
elif temperature > 10:
    print("A bit cool.")
else:
    print("It's cold!")
# Output: Nice and warm.

Nested Conditionals

score = 85
if score >= 50:
    if score >= 90:
        grade = "A"
    elif score >= 75:
        grade = "B"
    else:
        grade = "C"
else:
    grade = "F"
print(f"Grade: {grade}")  # Grade: B

Ternary (Conditional) Expression

age = 18
status = "adult" if age >= 18 else "minor"
print(status)  # adult

Truthiness

In Python, the following values are falsy: 0, 0.0, "", [], {}, None, False. Everything else is truthy.

name = ""
if name:
    print(f"Hello, {name}")
else:
    print("No name provided.")  # This runs