Python lesson 4

Making Decisions with If Statements

Teach Python to choose different paths. Like a Choose-Your-Own-Adventure story!

How Python Makes Decisions

If statements let your code choose what to do based on a condition. Is the age over 13? Take one path. Is it not? Take another. Python checks the condition and picks the right path!

if age >= 13:
print("Teen!") # runs when TRUE
else:
print("Kid!") # runs when FALSE

age = 15
if age >= 13:
    print("Teen!")
else:
    print("Kid!")

Which Path Does It Take?

age = 10
if age >= 13:
    print("Teen")
elif age >= 8:
    print("Kid")
else:
    print("Little")

If and Else

Click Run to see if/else in action. Then try changing age = 15 to age = 8 and click Run again!

Hint: Click Run first. Then change 15 to 8 and run again. Python picks the other message!

age = 15
if age >= 13:
    print("Teen!")
else:
    print("Kid!")

Three Choices with elif

Run this code. Then try changing temp to 30, then to 5. Does Python pick the right message each time?

Hint: Try temp = 30 for Hot day, temp = 20 for Nice day, temp = 5 for Cold day.

temp = 20
if temp > 25:
    print("Hot day!")
elif temp > 15:
    print("Nice day!")
else:
    print("Cold day!")

Secret Password Checker

Run the code. Then change the password to something wrong. What happens? Change it back to see it work!

Hint: Change "python123" to any other word and see the else branch run!

password = "python123"
if password == "python123":
    print("Access granted!")
else:
    print("Wrong password!")

What you can do on CodeIt

Run the example, change one part, and use the result to check your understanding before moving to the next lesson.