Chapter 9 Quiz >> Python Data Structures

Chapter 9 Quiz >> Python Data Structures


1. How are Python dictionaries different from Python lists?

  • Python dictionaries are a collection and lists are not a collection
  • Python lists are indexed using integers and dictionaries can use strings as indexes
  • Python lists store multiple values and dictionaries store a single value
  • Python lists can store strings and dictionaries can only store words

2. What is a term commonly used to describe the Python dictionary feature in other programming languages?

  • Associative arrays
  • Sequences
  • Lambdas
  • Closures

3. What would the following Python code print out?

stuff = dict()
print(stuff['candy'])
  • -1
  • The program would fail with a traceback
  • 0
  • candy

4. What would the following Python code print out?

stuff = dict()
print(stuff.get('candy',-1))
  • -1
  • ‘candy’
  • 0
  • The program would fail with a traceback

5.(T/F) When you add items to a dictionary they remain in the order in which you added them.

  • False
  • True

6. What is a common use of Python dictionaries in a program?

  • Splitting a line of input into words using a space as a delimiter
  • Sorting a list of names into alphabetical order
  • Building a histogram counting the occurrences of various strings in a file
  • Computing an average of a set of numbers

7. Which of the following lines of Python is equivalent to the following sequence of statements assuming that counts is a dictionary?

if key in counts:
counts[key] = counts[key] + 1
else:
counts[key] = 1
  • counts[key] = (counts[key] * 1) + 1
  • counts[key] = counts.get(key,-1) + 1
  • counts[key] = counts.get(key,0) + 1
  • counts[key] = key + 1
  • counts[key] = (key in counts) + 1

8.In the following Python, what does the for loop iterate through?

x = dict()

for y in x :
  • It loops through the keys in the dictionary
  • It loops through the values in the dictionary
  • It loops through all of the dictionaries in the program
  • It loops through the integers in the range from zero through the length of the dictionary

9. Which method in a dictionary object gives you a list of the values in the dictionary?

  • each()
  • values()
  • all()
  • keys()
  • items()

10. What is the purpose of the second parameter of the get() method for Python dictionaries?

  • To provide a default value if the key is not found
  • An alternate key to use if the first key cannot be found
  • The key to retrieve
  • The value to retrieve

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