Python Week 8
A comprehension always produces a list.
False
A dictionary is bidirectional — values can be used to look up keys and vice versa.
False
A dictionary key must be a character string.
False
A for loop can be used to traverse a dictionary's keys, but not its values.
False
All values stored in a Python dictionary must be unique.
False
In the Counting Letters examples, the dictionary used to keep track of letter frequencies uses the count as the key.
False
What does the Hello World Translator program use to look up the language used given a phrase?
A list comprehension
The Hello World Translator program will produce an error if the language requested is not in the dictionary.
False
When printed, a set containing strings will list the elements in alphabetical order.
False
A dictionary is designed for efficient value retrieval. True
True
Checking to see if an element is in a set is an efficient operation in Python.
True
The analysis of the complete I Have a Dream speech shows that four of the top five frequently used letters are vowels.
True
The dictionary used in the Hello World Translator program uses the language name as the key.
True
The if clause in a comprehension is optional.
True
Which of the following is NOT an appropriate use case for a Python dictionary?
Representing an ordered sequence of values
Which of the following statements is true when using a dictionary for counting?
The key is the item counted, the value is the count
A generator expression has the same basic syntax as a list comprehension.
True
Defining a class is an alternative to using a dictionary as a record.
True
In the Counting Letters examples, only letters found in the analyzed text have entries in the dictionary.
True
The codes used in Morse Code are influenced by the frequency of letter use in English communication. True
True
The content of the dictionary used in the Hello World Translator program is read from an input file. True
True
The items method returns a list of key/value tuples for all entries in a dictionary.
True
The result of a comprehension could always be created using more verbose code.
True
Using the index operator to retrieve a value will result in a KeyError if the key is not in the dictionary.
True
When using a dictionary as a record, the name of the attribute is used as the key.
True
What value will the variable my_list hold after the following line of code is executed? my_list = [num for num in range(1, 20) if num % 3 == 0]
[3, 6, 9, 12, 15, 18]
What value will the variable stuff hold after the following code is executed? state = 'Mississippi' stuff = {ch.lower() for ch in state if ch != 'i'}
{'m', 's', 'p'}
What set is stored in set3 by the following code? set1 = {1, 2, 3, 4, 5} set2 = {3, 4, 5, 6, 7, 8, 9} set3 = set1 | set2
{1, 2, 3, 4, 5, 6, 7, 8, 9} because you combine the two lists but do not contain any duplicates; so although both have 3, 4, and 5, you would only list them once.
What set is stored in set3 by the following code? set1 = {1, 2, 3, 4, 5} set2 = {3, 4, 5, 6, 7, 8, 9} set3 = set1 - set2
{1, 2} because that is set one if you remove anything that both set1 and set2 have listed.
What set is stored in set3 by the following code? set1 = {1, 2, 3, 4, 5} set2 = {3, 4, 5, 6, 7, 8, 9} set3 = set1 & set2
{3, 4, 5} because the & symbol submits anything that both sets have listed.
