Week 1

Question 1

What are values in programming?

Answer 1

A specific piece of data or information that a program can use, store, manipulate, or pass around.

Question 2

What are expressions in programming?

Answer 2

A combination of values, variables, operators, and functions that can be evaluated or computed to produce another value

Question 3

What are statements in programming?

Answer 3

A single instruction or command that a program executes.

Question 4

What is an interpreter in Python?

Answer 4

A program that reads a high level programming language and executes the instructions one line or statement at a time.

Question 5

What is the correct way to format floating point numbers in a print statement?

Answer 5

Print(f”{e:.#f}”)
With # as the number of decimal places

Question 6

What function is used to get user input?

Answer 6

The input() function

Question 7

What function is used to convert strings to integers?

Answer 7

The int() function

Question 8

What function is used to convert strings to floating point numbers?

Answer 8

The float() function

Question 9

What operator is used to do floor division?

Answer 9

The // operator

Question 10

What does _ mean in python?

Answer 10

It is a variable representing the last printed expression

Question 11

Are strings considered mutable or immutable?

Answer 11

Immutable

Question 12

What built in objects are considered false?

Answer 12

Constants “None” and “False”
Zero of any numeric type
Empty sequences and collections

Question 13

Do comparison or Boolean operators have higher priority?

Answer 13

Comparison operators

Question 14

What are the three distinct numeric types?

Answer 14

Int, float, complex

Question 15

How are constants formated in Python for CS 111?

Answer 15

Upper snake case

Question 16

How to you run a doctest in the terminal?

Answer 16

With the command “python3 -m doctest file.py” executed in the correct directory

Question 17

How do you run a pytest in the terminal?

Answer 17

With the command “python3 -m pytest -vv” in the correct directory

Question 18

What does “python -i file.py” do?

Answer 18

It runs your code and opens an interactive session

Question 19

Order the Boolean operators in order of priority:

Answer 19

1. Not (highest)
2. And
3. Or (lowest)

Question 20

What values are considered truths values?

Answer 20

True, non-zero integers, etc.

Question 21

What values are considered false values?

Answer 21

False, 0, None, [], etc.

Question 22

How do you “unpack” multiple return values from a function in Python?

Answer 22

a, b, … = function(argument, argument, …)

Question 23

Cs50P: How can you open two files at once with the “with” statement?

Answer 23

Use a comma to separate the statements:

With open(…) as file, open(…) as file2:

Question 24

What is a call expression?

Answer 24

It applies a function which may or may not accept arguments

Question 25

What is a call expression?

Answer 25

It applies a function which may or may not accept arguments

Question 26

How do you use slicing in Python?

Answer 26

name[start:end:step_size]

Question 27

Does slicing include or exclude the beginning and end?

Answer 27

Includes the beginning, excludes the end

Question 28

Does slicing include or exclude the beginning and end?

Answer 28

Includes the beginning, excludes the end

Question 29

Does slicing include or exclude the beginning and end?

Answer 29

Includes the beginning, excludes the end

Question 30

What are comprehensions?

Answer 30

A compact and powerful way of creating new lists out of sequences

Question 31

What is the simplest syntax for a list comprehension?

Answer 31

[expression_to_add for element in sequence]

Question 32

How do you reverse a string with slicing?

Answer 32

Reversed_string == string[::-1]

Question 33

How would you modify a golobal variable in a function?

Answer 33

With the global variable: global x

Question 34

What does the extend() function do in Python?

Answer 34

It is used to add items from one list or iterable to the end of another list

Question 35

What is best practice for handling close for a file that may raise an exception?

Answer 35

try:
file = open(“filename.txt”, “r”)
finally:
file.close()