Grade 10 Computer Science — Looping over a dictionary

1.A program sets total to 0 and then runs "for k in prices:" over the dictionary {"pen": 5, "bag": 10, "cup": 15}, with one of these lines as the body. Match each body to what total holds at the end.

2.Two separate loops here feed the same total, one after the other. What does the program print?

left = {"pen": 3, "bag": 4}
right = {"cup": 5}
total = 0
for k in left:
    total = total + left[k]
for k in right:
    total = total + right[k]
print(total)

3.This loop keeps hold of two things at once: the best value it has seen, and the key that value came from. Which word does the program print?

votes = {"red": 12, "blue": 30, "green": 21}
best = ""
top = 0
for name in votes:
    if votes[name] > top:
        top = votes[name]
        best = name
print(best)

4.This loop prints as it goes, and a dictionary is walked in the order its pairs were written. What is the last number it prints?

sizes = {"small": 2, "large": 7}
for name in sizes:
    print(sizes[name])

5.A loop counts how many of a dictionary's values are over 10. Put these dictionaries in order of that count, fewest first.

• {"pen": 12, "bag": 3}
• {"pen": 4, "bag": 2}
• {"pen": 15, "bag": 20, "cup": 30}
• {"pen": 11, "bag": 40, "cup": 2}

6.A loop over a dictionary is written as "for name in sizes:". What does name hold each time round?

• a) A position, counting from 0
• b) A whole pair, key and value together
• c) One of the keys
• d) One of the values

7.There is a decision inside this loop, so not every key adds to the counter. What does the program print?

sales = {"north": 12, "south": 30, "east": 5, "west": 22}
busy = 0
for place in sales:
    if sales[place] > 20:
        busy = busy + 1
print(busy)

8.A dictionary is built from scratch inside this loop, and one thing in the list turns up twice. What does the program print?

counts = {}
for word in ["pen", "bag", "pen"]:
    counts[word] = 1
print(len(counts))