Concepts on Quiz 3

Before working through these practice questions, you should first carefully read this page on Quiz Expectations.

Quiz 3 will cover the following concepts:

Questions

The quiz itself will be similar in difficulty but longer in length than this practice worksheet.

Solutions for each problem can be found at the bottom of this page.

To access a value in a dictionary, you use the format dictionary_name{key}. (T/F)
Multiple keys can have the same value. (T/F)
The values in a dictionary cannot be changed after the dictionary is constructed. (T/F)
The not in operator can be used to check whether a specific key exists in a dictionary. (T/F)
For the purposes of this course, all values in a dictionary are of the same type. (T/F)
Dictionaries can have lists or other dictionaries as their keys. (T/F)
In a Jupyter Notebook, you may evaluate the cells in any order. (T/F)
You should write comments in a Python cell to narrate your code in a Jupyter Notebook. (T/F)
Cells will automatically print output below them if the final line of the code assigns a value to a variable. (T/F)
Restarting the Jupyter notebook’s kernel erases all of its variables that were previously assigned by running cells. (T/F)

Produce a memory diagram for the following code snippet, being sure to include its stack and output.
11.1 Describe in words what the scan function does.
Produce a memory diagram for the following code snippet, being sure to include its stack and output.

Write a function called dict_transform. Given a dictionary with int keys and list[int] values, dict_transform should return the dictionary with every value in a list multiplied by its corresponding key.
Example: dict_transform({ 2:[1,2] , 5:[3,4] }) returns { 2:[2,4] , 5:[15,20] }.
Write a function called average_grades. Given a dictionary with str keys and list[int] values, average_grades should return a new dictionary of type dict[str, float] that maps each student to their average.
Example: average_grades({ ‘Bill’:[75, 94, 97] , ‘Annie’:[88, 93, 99] }) returns { ‘Bill’:88.67 , ‘Annie’:93.33 }.

11.1 The scan function takes in a dictionary and returns a list of the names of people that are 21 and older.