Sets – Basics
Name:
Date:
Class:
A
Quick Questions
Shade in the A or B circle for each question.
1. What is a nested list?
2. grid = [[1,2],[3,4]]\ngrid[0] returns?
3. grid = [[1,2],[3,4]]\ngrid[0][1] returns?
4. grid = [[1,2],[3,4]]\ngrid[1][0] returns?
5. How do you loop through all items in a nested list?
B
Match the Pairs
Draw a line connecting each item on the left to its match on the right.
| Left column | Right column | |
|---|---|---|
| 1g = [[1,2],[3,4]] print(g[2][0]) | AError: Use g[0][1] not g[0,1] | |
| 2g = [[1,2],[3,4]] print(g[0,1]) | BOutput: 2 | |
| 3g = [[1,2],[3,4]] g[0][1] | CValid: Returns 2 | |
| 4for row in g: for item in row: print(item) | DError: Row index 2 out of range | |
| 5g = [[1,2],[3,4]] print(g[1][0]) | EOutput: 3 | |
| 6g = [[1,2],[3,4]] print(len(g)) | FOk: Nested loops to traverse |
C
Definitions
Nested list
D
Fill in the Blanks
Complete each line of code by filling in the missing parts.
1.
grid = [[1, 2], [3, 4]]
print(grid[_][1])
2.
grid = [[1, 2], [3, 4]]
print(grid[1][_])
3.
for ___ in grid:
for item in row:
print(item)
4.
grid = [[1, 2], [3, 4]]
print(___( grid))
5.
grid = [[1, 2], [3, 4]]
grid[0][0] = __
print(grid)
E
Spot the Error
Shade in the letter of the line that contains an error.
Question 1
A
grid = [[1, 2], [3, 4]]
B
print(grid[0, 1])
Question 2
A
grid = [[1, 2], [3, 4]]
B
print(grid[2][0])
Question 3
A
grid = [[1, 2], [3, 4]]
B
for item in grid:
C
print(item) # expects individual numbers
Question 4
A
grid = [1, 2], [3, 4]
B
first_row = grid[0]
C
print('First row:', first_row)
D
print('Item:', grid[0][1])
Question 5
A
grid = [[1, 2], [3, 4]]
B
print(grid[0][1][0])
Answer Key
Sets – Basics
Section A: Quick Questions
Q1
A — A list inside another list
Q2
A — [1, 2]
Q3
B — 2
Q4
A — 3
Q5
B — Two nested for loops
Section B: Match the Pairs
Q1
g = [[1,2],[3,4]]
print(g[2][0]) → Error: Row index 2 out of range
Q2
g = [[1,2],[3,4]]
print(g[0,1]) → Error: Use g[0][1] not g[0,1]
Q3
g = [[1,2],[3,4]]
g[0][1] → Valid: Returns 2
Q4
for row in g:
for item in row:
print(item) → Ok: Nested loops to traverse
Q5
g = [[1,2],[3,4]]
print(g[1][0]) → Output: 3
Q6
g = [[1,2],[3,4]]
print(len(g)) → Output: 2
Section C: Definitions
Q1
Nested list — A list that contains other lists as elements.~~grid[row][col]Section D: Fill in the Blanks
Q1
grid = [[1, 2], [3, 4]]
print(grid[0][1])Q2
grid = [[1, 2], [3, 4]]
print(grid[1][1])Q3
for row in grid:
for item in row:
print(item)Q4
grid = [[1, 2], [3, 4]]
print(len( grid))Q5
grid = [[1, 2], [3, 4]]
grid[0][0] = 99
print(grid)Section E: Spot the Error
Q1
B — Use two separate brackets grid[0][1], not a comma grid[0, 1]
Q2
B — grid has indices 0 and 1. Index 2 is out of range.
Q3
B — One loop gives inner lists [1,2] and [3,4]. Need nested loops for individual items.
Q4
A — Missing outer brackets: this creates a tuple of lists, not a list of lists
Q5
B — grid[0][1] is 2 (an integer). Can't index into a number.