Conditionals

A conditional lets the program choose. Python checks a condition - something that is either true or false - and runs the indented lines under it only if the condition is true. With if, elif, and else, a program can react one way to a right answer, another to a close answer, and another to a wrong one. That is how a game decides whether you scored, won, or lost.

• Write an if statement that runs only when a condition is true.
• Add elif and else to handle the other answers.
• Compare the player's answer to an expected value with ==.
• Fix the common mix-up between = and ==.

condition

A question with a true or false answer, like answer == "Earth".

if

Runs the indented lines below it only when its condition is true.

elif

Checks another condition when the ones above it were false.

else

Runs when none of the conditions above it were true.

==

Checks whether two values are equal (different from =, which stores a value).

Edit the starter code below and press Run to see it work. Use Reset starter code to go back to the original at any time.

Expected output

Which planet do we live on? Earth
Correct! 1 point.

Add a second question with its own if / else, so your quiz has two questions in a row.

Python shows an error on the if line. One equals sign stores a value in a variable. What do you use when you want to check whether two things are the same?

Broken code

answer = input("Which planet do we live on? ")
if answer = "Earth":
    print("Correct!")

Comparing two values needs two equals signs:
if answer == "Earth":

Turn it into a personality quiz: ask a would-you-rather question and print a different result for each choice using if, elif, and else.

Your program now reacts differently to different answers. In your final game, what is one decision the program will need to make, and what should happen for each choice?

Facilitating this lesson? See the teacher & librarian guide for how to run it, common mistakes, and an offline backup activity.