Python: Loops, Lists and Functions: Unit Exam B
Reading range(), counting down with while, changing lists, a times table program to write, functions, validation loops and choosing a loop.
Instructions
- Time allowed
- 25 minutes
- Total marks
- 25
- Calculator
- No calculator is permitted.
- Answer all the questions.
- The number of marks for each question is shown in brackets. Use it as a guide to how much to write.
- The clock at the top counts down from the real time allowed. When it reaches zero the paper is locked and marked, as it would be collected in the exam hall.
- Read every question to the end before answering. Where a question says tick two boxes, tick exactly two: ticking more than asked scores nothing. Type one word and number answers carefully, because they are marked exactly.
Questions
Answer every question, then finish the paper to have it marked. Marking as you go teaches you far less.
for i in range(5):
print(i)- L0
range(5) starts at 0.
- L6
2, 3, 4, 5, 6 and 7: six numbers, stopping before 8.
count = 10
while count > 0:
count = count - 3
print(count)- L-2
10, 7, 4, 1, then -2. -2 is not above 0, so the loop stops and prints -2.
- Lhamster
- Lrabbit
- L4
- Lcat
rabbit is added at index 3, and index 1 is replaced by hamster, giving cat, hamster, fish, rabbit.
Tick one box.
- LB for i in range(1, 11): print(i)
range(1, 11) starts at 1 and stops before 11.
- LUses a loop
- LPrints 3, 6, 9, 12 and 15 for 3
- LWorks for any number: 7, 14, 21, 28 and 35 for 7
Loop i from 1 to 5 with range(1, 6), printing i * n each time.
n = int(input("Number: "))
for i in range(1, 6):
print(i, "x", n, "=", i * n)Tick one box.
- LD The number of items in the list
len() counts the items.
def greet(name):
return "Hi " + name
message = greet("Ana")
print(message + "!")- LHi Ana!
greet returns Hi Ana, and the ! is added before printing.
Tick one box.
- LC A parameter is passed into a function; a return value is sent back out of it
Values go in through parameters and come out through return.
- LCode can be reused without writing it again
- LPrograms are easier to read, test and fix, because they are split into named parts
A function is written once and called whenever it is needed, so code is not repeated. Splitting a program into named functions also makes it easier to read, and each part can be tested and fixed on its own.
age = int(input("Age: "))
while age < 11 or age > 18:
print("Invalid")
age = int(input("Age: "))
print("Accepted")| Line | Output |
|---|---|
| 1 | |
| 2 | |
| 3 |
- LInvalid
- LInvalid
- LAccepted
9 is below 11, so Invalid. 25 is above 18, so Invalid. 14 is in range, so the loop ends and Accepted is printed.
Tick one box.
- LA Range check
A range check tests that a value lies between limits.
| for loop | while loop | |
|---|---|---|
| Print each item in a shopping list | ||
| Keep asking until the user types quit | ||
| Repeat exactly 20 times | ||
| Keep rolling a dice until it shows a six |
Tick one box in each row.
- LPrint each item in a shopping list: for loop
- LKeep asking until the user types quit: while loop
- LRepeat exactly 20 times: for loop
- LKeep rolling a dice until it shows a six: while loop
Use for when the number of repeats is known, and while when you repeat until something happens.
nums = [5, 10, 15]
total = 0
for n in nums:
total = total + n
print(total / len(nums))- L10
The total is 30 and there are 3 items: 30 / 3 = 10.0.
This is an original Key Stage 3 assessment. Most questions are closed, so the marking is exact, and the written answers are marked against a mark scheme in the same style as a GCSE paper, so the format is familiar long before it counts.