CASE as if/elif/else in Python
Name:
Date:
Class:
A
Quick Questions
Shade in the A or B circle for each question.
1. Python has no CASE statement. How do you write CASE OF Move in Python?
2. Which keyword does the FIRST value of a CASE OF Move become in Python?
3. Which line is the correct Python for the second value in a CASE OF Move?
4. The pseudocode has OTHERWISE OUTPUT "Invalid". How is this written in Python?
5. Which is the correct way to write the end of a CASE OF Move as Python?
B
Match the Pairs
Draw a line connecting each item on the left to its match on the right.
| Left column | Right column | |
|---|---|---|
| 1elif Move == "B": | Aif Move == "F": | |
| 2else: | BTests the next CASE value after the first, like the line B: in a CASE OF Move statement | |
| 3The first value in CASE OF Move becomes an if that tests the variable Move | CThe second value uses if instead of elif, so it is a separate test and not part of the same chain. It should be elif Move == "B": | |
| 4Every value in the chain tests the same variable, so each elif compares Move again | DOTHERWISE does not exist in Python. The catch-all branch must be written as else: | |
| 5if Move == "F": print("Forward") if Move == "B": print("Back") | Eelif Move == "L": | |
| 6elif Move == "B": print("Back") OTHERWISE: print("Invalid") | FRuns when none of the if or elif tests match, just like OTHERWISE in a CASE statement |
C
Definitions
if/elif/else
D
Fill in the Blanks
Complete each line of code by filling in the missing parts.
1.
__ move == "L":
print("Left")
elif move == "R":
2.
if move == "L":
print("Left")
____ move == "R":
3.
elif move == "R":
print("Right")
____:
4.
if move __ "L":
print("Left")
elif move == "R":
5.
if move == "L":
print("Left")
elif ____ == "R":
E
Spot the Error
Shade in the letter of the line that contains an error.
Question 1
A
move = input("Move: ")
B
if move = "L":
C
print("Left")
D
elif move == "R":
E
print("Right")
Question 2
A
move = input("Move: ")
B
if move == "F"
C
print("Forward")
D
else:
E
print("Invalid")
Question 3
A
move = input("Move: ")
B
elif move == "U":
C
y = y + 1
D
elif move == "D":
E
y = y - 1
Question 4
A
move = input("Move: ")
B
if move == "U":
C
print("Up")
D
otherwise:
E
print("Unknown move")
Question 5
A
if move == "L":
B
x = x - 1
C
else if move == "R":
D
x = x + 1
Answer Key
CASE as if/elif/else in Python
Section A: Quick Questions
Q1
A — An if/elif/else chain that tests Move each time
Q2
B — if Move == "L":
Q3
A — elif Move == "R":
Q4
B — else:
Q5
A — else: followed by an indented print("Invalid")
Section B: Match the Pairs
Q1
elif Move == "B": → Tests the next CASE value after the first, like the line B: in a CASE OF Move statement
Q2
else: → Runs when none of the if or elif tests match, just like OTHERWISE in a CASE statement
Q3
The first value in CASE OF Move becomes an if that tests the variable Move → if Move == "F":
Q4
Every value in the chain tests the same variable, so each elif compares Move again → elif Move == "L":
Q5
if Move == "F":
print("Forward")
if Move == "B":
print("Back") → The second value uses if instead of elif, so it is a separate test and not part of the same chain. It should be elif Move == "B":
Q6
elif Move == "B":
print("Back")
OTHERWISE:
print("Invalid") → OTHERWISE does not exist in Python. The catch-all branch must be written as else:
Section C: Definitions
Q1
if/elif/else — Python has no CASE, so write it as an if/elif chain testing the same variable. The first value uses if, each other value uses elif, and OTHERWISE becomes else.Section D: Fill in the Blanks
Q1
if move == "L":
print("Left")
elif move == "R":Q2
if move == "L":
print("Left")
elif move == "R":Q3
elif move == "R":
print("Right")
else:Q4
if move == "L":
print("Left")
elif move == "R":Q5
if move == "L":
print("Left")
elif move == "R":Section E: Spot the Error
Q1
B — A single = assigns a value. To test whether move equals "L" you need the comparison operator ==, so the line should be if move == "L":.
Q2
B — Every if line in Python must end with a colon. The line should be if move == "F":.
Q3
B — The first value of the CASE must use if, not elif. An elif cannot start a chain because there is no if before it. It should be if move == "U":.
Q4
D — Python has no OTHERWISE keyword. OTHERWISE in a CASE statement becomes else: in Python.
Q5
C — Python does not use else if. Each extra value in the CASE is written as elif, so the line should be elif move == "R":.