project stem assignment 9 2d arrays

# Project Stem

Source code for the 2022-23 AP Computer Science A course on Project Stem.

# 📃 About

This page contains the source code to various problems on Project Stem. Organized by unit, you will find the necessary activity files to be compiled by the Java environment, as well as runner files provided by Project Stem to test execution (when available).

The provided source code is intended to work with the 2023 AP CS A course. These solutions may grow out-of-date as new changes are made to the course every year.

# Table of Contents

• Unit 1: Primitive Types
• Unit 2: Using Objects
• Unit 3: Boolean Expressions and If Statements
• Unit 4: Iteration
• Unit 5: Writing Classes
• Unit 6: Array
• Unit 7: ArrayList
• Unit 8: 2D Array
• Unit 9: Inheritance
• Unit 10: Recursion

# 📝 Contributing

Notice a typo or error? Feel free to create an issue !

Please note that support will not be provided for code that does not work in newer lessons.

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Project stem unit 9 test NEED ANSWERS ASAP

Please help this is literally my final

Question 1 In row-major two-dimensional lists, when accessing an element, the __________ is always listed first. Group of answer choices

Flag question: Question 2 Question 2 1 pts For questions 2 and 3, consider the following two-dimensional list:

What is the element at [2][3]?

Group of answer choices

Flag question: Question 3 Question 3 1 pts What is the element at [2][2]? Group of answer choices

Flag question: Question 4 Question 4 1 pts Which of the following is true about lists? Group of answer choices

The first number when accessing a two-dimensional list gives the column number

Lists can only be one-dimensional

Elements refer to the locations of a piece of data in the list

Indexes refer to the locations of a piece of data in the list

Flag question: Question 5 Question 5 1 pts What does it mean for a list to be column-major? Group of answer choices

The elements first refer to the column and then the row

All data is stored in columns

The list has a maximum of one row

The indexes first refer to the column and then the row

Flag question: Question 6 Question 6 1 pts Which of the following lines of code correctly create a two-dimensional list? Group of answer choices

stuff = [3, 4, 5], [6, 3, 1]

stuff = [[3, 4, 5],[6, 3, 1]]

stuff = [3, 4, 5] + [6, 3, 1]

stuff = [3, 4, 5][6, 3, 1]

Flag question: Question 7 Question 7 1 pts Consider the following code:

row.append(1)

row.append(3)

row.append(7)

grid.append(row)

grid.append(row) What are the dimensions of grid (row x column)?

Flag question: Question 8 Question 8 1 pts Consider the following code:

temp.append([53, 12, 24, 86, 23])

temp.append([33, 77, 47, 58, 43])

temp.append([73, 42, 15, 82, 32])

print(temp[2][1]) What is output by the code?

Flag question: Question 9 Question 9 1 pts Consider the following code:

list = [[1,5,3], [4,9,7]]

list.append([2,7,9]) How many rows does the two-dimensional list now contain?

Flag question: Question 10 Question 10 1 pts Consider the following code:

grid.append (["emu", "hedgehog", "cat"])

grid.append (["fish", "frog", "dog"])

grid.append (["rooster", "iguana", "llama"])

print(grid[0][1]) What is output by the code?

Flag question: Question 11 Question 11 1 pts Which of the following statements are true? Group of answer choices

Numerical calculations can be performed using a single for loop on two-dimensional lists

Two-dimensional lists have to store the same type of element across each column

Numerical calculations on two-dimensional lists require two for loops

Two-dimensional lists have to store the same type of element across each row

Flag question: Question 12 Question 12 1 pts Consider the following code that stores values in a 5 x 3 list called grid:

grid.append (["frog", "cat", "hedgehog"])

grid.append (["fish", "emu", "rooster"])

grid.append (["dog", "bird", "rabbit"])

grid.append (["deer", "chipmunk", "opossum"])

grid.append (["fox", "coyote", "wolf"])

for r in range (len(grid)):

for c in range (len(grid[0])):

After this code is run, what values does the list grid hold?

Flag question: Question 13 Question 13 1 pts Which method would correctly swap two rows of a two-dimensional list? Group of answer choices

def swapRows (grid, a, b):

Flag question: Question 14 Question 14 1 pts Which of the following loops would change the list grid to the following values? Assume that grid is already a 2D list with 4 rows and 3 columns.

for r in range(len(grid)):

for c in range(len(grid[0])):

grid[r][c] = f * 2

grid[r][c] = f

grid[r][c] = r + c

Flag question: Question 15 Question 15 1 pts Which of the following loops would change the list grid to the following values? Assume that grid is already a 2D list with 4 rows and 3 columns.

grid[r][c] = c + 1

grid[r][c] = r + 1

grid[r][c] = r

Flag question: Question 16 Question 16 1 pts Consider the following two-dimensional list:

72 57 97 63 85

84 42 90 61 88

98 43 54 86 55

Which loop correctly adds up the values in the third column (beginning with 97)?

for i in range(len(a)):

sum = sum + a[i][2]

sum = sum + a[3][i]

sum = sum + a[i][3]

sum = sum + a[2][i]

Flag question: Question 17 Question 17 1 pts Which of the following loops would correctly initialize a 13 x 15 two-dimensional list to random 2-digit numbers? You can assume the list vals has been declared and random has been imported. Group of answer choices

for r in range(15):

vals.append([])

for c in range(13):

vals[r][c] = random.randint(10,99)

for r in range(13):

for c in range(15):

vals[r].append(random.randint(10,99))

Flag question: Question 18 Question 18 1 pts Consider the two-dimensional list below:

Which position is the number 5 located at?

Flag question: Question 19 Question 19 1 pts Consider the following code:

grid.append([])

grid[0].append(9)

grid[0].append(7)

grid[1].append(5)

grid[1].append(3)

grid[2].append(2)

grid[2].append(8)

grid[3].append(1)

grid[3].append(3) How many rows and columns does this list have?

4 rows and 2 columns

2 rows and 4 columns

4 rows and 4 columns

2 rows and 2 columns

Flag question: Question 20 Question 20 1 pts What type of variable is available to all methods in a program? Group of answer choices

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