Python 24-Day Course - Day 5: Conditional Statements

Day 5: Conditional Statements

if / elif / else

score = 85

if score >= 90:
    grade = "A"
elif score >= 80:
    grade = "B"
elif score >= 70:
    grade = "C"
else:
    grade = "F"

print(f"Grade: {grade}")  # Grade: B

Ternary Operator

You can express a condition in a single line.

age = 20
status = "adult" if age >= 18 else "minor"
print(status)  # adult

Combining Logical Operators

temperature = 25
humidity = 60

if temperature > 20 and humidity < 70:
    print("Pleasant weather")
elif temperature > 35 or humidity > 85:
    print("Uncomfortable weather")

Truthy and Falsy

These are the values that evaluate to false in Python.

Falsy Value	Description
`False`	Boolean false
`0`, `0.0`	Numeric zero
`""`	Empty string
`[]`, `()`, `{}`	Empty collections
`None`	No value

items = []
if not items:
    print("The list is empty")

name = ""
username = name or "anonymous"
print(username)  # anonymous

Today’s Exercises

Write a program that takes a year as input and determines whether it is a leap year.
Take three numbers as input and print the largest one (without using the max function).
Calculate BMI and classify it as underweight/normal/overweight/obese.