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Practice Quiz 6 (Ch 11–12)

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Question 1  (3 pts)

Consider the list of lists: 

words = [
    ["apple", "alligator", "awesome"],
    ["bee", "barn", "berry"],
    ["cat", "celery", "candle"],
    ["dog", "dark", "dress"],
]

  • How many rows are there?   4
  • How many columns are there?   3
  • How do you access the string "berry"?   words[1][2]
  • What is the output of print(words[2])?   ['cat', 'celery', 'candle']

 

Question 2  (2 pts)

Consider the dictionary of lists: 

schedule = {
    "MWF": ["9:35am", "12:15pm", "2:30pm"],
    "TR": ["11:10am", "4:20pm"],
}

  • List the keys, separated by commas:   "MWF", "TR"
  • Write a statement to append "5:00pm" to the "TR" list:   schedule["TR"].append("5:00pm")

 

Question 3  (2 pts)

results = [num*2 + 1 for num in range(5)]
print(results)

What is output by the code?   [1, 3, 5, 7, 9]

 

Question 4  (3 pts)

Consider the following function: 

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2
3
4
5
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7
8
def timer(num):
    print(num, end=" ")
    if num == 0:
        print("Done!")
    else:
        timer(num - 1)

timer(4)

  • Which line number contains the base case?   3
  • How many times is the function called?   5
  • What is the output?   4 3 2 1 0 Done!

 

Question 5  (3 pts)

Consider the following function: 

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def something(num1, num2):
    if num2 == 1:
        return num1
    else:
        return num1 + something(num1, num2 - 1)

  • What line number contains the recursive call?   5
  • What value is returned by something(4, 3)?   12
  • What value is returned by something(3, 0)?   RecursionError

 

Question 6  (5 pts)

Implement the following function. Please write clearly and indent your code using four spaces.

Hint: You can write this function in one line using a list comprehension.

def sum_rows(numbers):
    """Given a two-dimensional list of integers, add the integers
    in each row and return a list of the sums. If numbers is empty,
    return an empty list.

    Args:
        numbers (list): two-dimensional list of integers

    Returns:
        list: the sum of each row

    Example:
        sum_rows([[1, 34, 6], [3, 5, 8]]) returns [41, 16]
    """

    return [sum(row) for row in numbers]

    # 1 pts: build and return list
    # 2 pts: for row in numbers
    # 2 pts: append sum(row)

 

Question 7  (7 pts)

def skyscrapers(data, city, floors):
    """Find skyscrapers in a city that have a minimum number of floors.

    Args:
        data (list): JSON object of all known skyscrapers
        city (str): the city of interest
        floors (int): minimum number of floors

    Returns:
        list: names of skyscrapers that match the city and floors

    The JSON data is formatted as follows:
        [
            {
                "id": 12,
                "material": "steel",
                "name": "The Illinois",
                "location": {
                    "city": "Chicago",
                    "state": "Illinois",
                },
                "statistics": {
                    "height": 1609.3599853516,
                    "floors above": 528,
                    "number of purposes": 4,
                },
            },
            # other skyscraper dictionaries
        ]
    """

    return [item["name"] for item in data
            if item["location"]["city"] == city
            and item["statistics"]["floors above"] >= floors]

    # 1 pts: build and return list
    # 1 pts: for item in data
    # 2 pts: if item["location"]["city"] == city
    # 2 pts: and item["statistics"]["floors above"] >= floors
    # 1 pts: append item["name"]