Plt.subplots with rows and columns in Matplotlib - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a figure and axes with 2 rows and 1 column using plt.subplots.

Matplotlib

fig, axes = plt.subplots([1], 1)

Drag options to blanks, or click blank then click option'

A3

B1

C2

D4

Attempts:

3 left

💡 Hint

Common Mistakes

Using the number of columns as the first argument.

Forgetting to specify the number of rows.

The plt.subplots function takes the number of rows as the first argument. To create 2 rows and 1 column, use 2 as the first argument.

2fill in blank

medium

Complete the code to create a figure with 3 rows and 2 columns of subplots.

Matplotlib

fig, axes = plt.subplots([1], 2)

Drag options to blanks, or click blank then click option'

A3

B1

C2

D4

Attempts:

3 left

💡 Hint

Common Mistakes

Swapping rows and columns.

Using 2 instead of 3 for rows.

To create 3 rows and 2 columns, the first argument should be 3.

3fill in blank

hard

Fix the error in the code to create a 2x2 grid of subplots.

Matplotlib

fig, axes = plt.subplots(2, [1])

Drag options to blanks, or click blank then click option'

A1

B4

C3

D2

Attempts:

3 left

💡 Hint

Common Mistakes

Using 1 instead of 2 for columns.

Confusing rows and columns.

To create a 2 by 2 grid, both rows and columns should be 2.

4fill in blank

hard

Fill both blanks to create a 3x3 grid of subplots and set the figure size to 9x9 inches.

Matplotlib

fig, axes = plt.subplots([1], [2], figsize=(9, 9))

Drag options to blanks, or click blank then click option'

A3

B2

C4

D1

Attempts:

3 left

💡 Hint

Common Mistakes

Using different numbers for rows and columns.

Forgetting to set both to 3.

To create a 3 by 3 grid, both rows and columns should be 3.

5fill in blank

hard

Fill all three blanks to create a 2x3 grid of subplots, set figure size to 10x6 inches, and assign the axes to a variable.

Matplotlib

fig, [1] = plt.subplots([2], [3], figsize=(10, 6))

Drag options to blanks, or click blank then click option'

Aaxes

B2

C3

Dfigsize

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong variable names for axes.

Swapping rows and columns numbers.

The variable to hold axes is usually named axes. For 2 rows and 3 columns, use 2 and 3 respectively.

Practice

1. What does plt.subplots(2, 3) create in matplotlib?

easy

A. A figure with 2 rows and 3 columns of subplots

B. A figure with 3 rows and 2 columns of subplots

C. A single plot with size 2x3 inches

D. A figure with 6 rows and 1 column of subplots

Solution

1. Step 1: Understand plt.subplots parameters

   The first parameter is the number of rows, the second is columns.

2. Step 2: Apply to given code

   plt.subplots(2, 3) means 2 rows and 3 columns of subplots.

3. Final Answer:

   A figure with 2 rows and 3 columns of subplots -> Option A

4. Quick Check:

   rows=2, columns=3 = B [OK]

Hint: First number = rows, second = columns in plt.subplots [OK]

Common Mistakes:

• Confusing rows and columns order
• Thinking parameters set figure size
• Assuming single plot created

2. Which of the following is the correct syntax to create a 3x1 subplot grid using plt.subplots?

easy

A. fig, axes = plt.subplots(1, 3)

B. fig, axes = plt.subplots(3)

C. fig, axes = plt.subplots(3, 1)

D. fig, axes = plt.subplots(rows=3, cols=1)

Solution

1. Step 1: Recall plt.subplots parameter order

   The first argument is rows, second is columns.

2. Step 2: Match to 3 rows and 1 column

   plt.subplots(3, 1) creates 3 rows and 1 column.

3. Final Answer:

   fig, axes = plt.subplots(3, 1) -> Option C

4. Quick Check:

   3 rows, 1 column = C [OK]

Hint: Remember: plt.subplots(rows, columns) order matters [OK]

Common Mistakes:

• Swapping rows and columns
• Using single number for both dimensions
• Using keyword arguments incorrectly

3. What is the shape of axes returned by fig, axes = plt.subplots(2, 2)?

medium

A. A 1D array with 4 axes objects

B. A 2D array with shape (2, 2) of axes objects

C. A list of 2 axes objects

D. A single axes object

Solution

1. Step 1: Understand axes shape for multiple rows and columns

   When rows and columns are more than 1, axes is a 2D array matching shape.

2. Step 2: Apply to plt.subplots(2, 2)

   axes will be a 2x2 array of axes objects.

3. Final Answer:

   A 2D array with shape (2, 2) of axes objects -> Option B

4. Quick Check:

   Multiple rows and columns = 2D axes array [OK]

Hint: Multiple rows & columns -> axes is 2D array [OK]

Common Mistakes:

• Assuming axes is always 1D
• Confusing number of axes with shape
• Expecting a single axes object

4. Given the code:

fig, axes = plt.subplots(2, 2)
axes[2, 0].plot([1, 2, 3])

What error will occur?

medium

A. No error, plot will display

B. TypeError: axes object is not subscriptable

C. AttributeError: 'AxesSubplot' object has no attribute 'plot'

D. IndexError: index 2 is out of bounds for axis 0 with size 2

Solution

1. Step 1: Check axes shape from plt.subplots(2, 2)

   axes is a 2x2 array with indices 0 and 1 for rows and columns.

2. Step 2: Analyze axes[2, 0] access

   Index 2 for rows is out of bounds since max index is 1.

3. Final Answer:

   IndexError: index 2 is out of bounds for axis 0 with size 2 -> Option D

4. Quick Check:

   axes shape (2,2), index 2 invalid [OK]

Hint: Check axes array shape before indexing [OK]

Common Mistakes:

• Using invalid indices beyond shape
• Confusing axes as list instead of array
• Expecting no error on wrong index

5. You want to create a 2x3 grid of subplots and plot a line on each subplot with data from a list of 6 arrays. Which code correctly accesses each subplot to plot inside a nested loop?

hard

A. for i in range(2):
for j in range(3):
axes[i][j].plot(data[i*3 + j])

B. for i in range(2):
for j in range(3):
axes[i, j].plot(data[i + j])

C. for i in range(3):
for j in range(2):
axes[i][j].plot(data[i*2 + j])

D. for i in range(2):
for j in range(3):
axes[j][i].plot(data[i*3 + j])

Solution

1. Step 1: Understand axes shape and indexing

   plt.subplots(2, 3) creates axes as a 2x3 array, indexed as axes[row][col].

2. Step 2: Correctly map data list to subplot indices

   Data index = row * number_of_columns + column = i*3 + j matches subplot position.

3. Final Answer:

   for i in range(2): for j in range(3): axes[i][j].plot(data[i*3 + j]) -> Option A

4. Quick Check:

   axes[row][col], data index = row*cols + col [OK]

Hint: Use axes[row][col] and data index = row*cols + col [OK]

Common Mistakes:

• Swapping row and column loops
• Incorrect data indexing
• Using axes[j][i] instead of axes[i][j]