Unequal subplot sizes in Matplotlib - Mini Project: Build & Apply

Unequal subplot sizes

📖 Scenario: You are creating a simple data visualization for a report. You want to show two charts side by side, but one chart should be bigger than the other to highlight its importance.

🎯 Goal: Build a matplotlib figure with two subplots arranged horizontally. The left subplot should be twice as wide as the right subplot.

📋 What You'll Learn

Create a matplotlib figure with two subplots arranged in one row

Use gridspec_kw to set the width ratios of the subplots to 2 and 1

Plot simple line charts on each subplot

Display the figure with plt.show()

💡 Why This Matters

🌍 Real World

In reports or presentations, some charts need more space to show details clearly. Unequal subplot sizes help highlight important data visually.

💼 Career

Data analysts and scientists often customize plots to communicate insights effectively. Knowing how to adjust subplot sizes is a useful skill.

1

Create sample data

Create two lists called x and y1 with values [1, 2, 3, 4, 5] and [1, 4, 9, 16, 25] respectively.

Matplotlib

# Create lists x and y1 with the given values
# Your code here

Hint

Use square brackets to create lists. For example, x = [1, 2, 3].

2

Add second data list

Create a list called y2 with values [25, 16, 9, 4, 1].

Matplotlib

x = [1, 2, 3, 4, 5]
y1 = [1, 4, 9, 16, 25]
# Create list y2 with the given values
# Your code here

Hint

Remember to use square brackets and commas to separate values.

3

Create figure with unequal subplot sizes

Import matplotlib.pyplot as plt. Create a figure and two subplots in one row using plt.subplots() with nrows=1, ncols=2, and gridspec_kw={'width_ratios': [2, 1]}. Plot x vs y1 on the first subplot and x vs y2 on the second subplot.

Matplotlib

x = [1, 2, 3, 4, 5]
y1 = [1, 4, 9, 16, 25]
y2 = [25, 16, 9, 4, 1]
# Import matplotlib.pyplot as plt
# Create figure and subplots with width ratios 2 and 1
# Plot x vs y1 on first subplot
# Plot x vs y2 on second subplot
# Your code here

Hint

Use plt.subplots() with gridspec_kw to set different widths for subplots.

4

Display the figure

Add a line to display the figure using plt.show().

Matplotlib

import matplotlib.pyplot as plt

x = [1, 2, 3, 4, 5]
y1 = [1, 4, 9, 16, 25]
y2 = [25, 16, 9, 4, 1]

fig, (ax1, ax2) = plt.subplots(nrows=1, ncols=2, gridspec_kw={'width_ratios': [2, 1]})
ax1.plot(x, y1)
ax2.plot(x, y2)
# Display the figure
# Your code here

Hint

Use plt.show() to display the plot window.

Practice

1. What is the main advantage of using unequal subplot sizes in matplotlib?

easy

A. To automatically adjust colors of the plots

B. To make all charts the same size for uniformity

C. To highlight important charts by giving them more space

D. To reduce the total number of charts displayed

Solution

1. Step 1: Understand subplot size purpose

   Unequal subplot sizes allow some plots to be larger, drawing more attention.

2. Step 2: Compare options

   Only To highlight important charts by giving them more space mentions highlighting important charts by size, which is the main advantage.

3. Final Answer:

   To highlight important charts by giving them more space -> Option C

4. Quick Check:

   Unequal sizes highlight key charts [OK]

Hint: Unequal sizes = emphasize important plots [OK]

Common Mistakes:

• Thinking all subplots must be equal size
• Confusing size with color or number of plots
• Assuming unequal sizes reduce charts

2. Which of the following is the correct way to create subplots with unequal sizes using gridspec_kw in plt.subplots()?

easy

A. plt.subplots(1, 2, gridspec_kw={'width_ratios': [2, 1]})

B. plt.subplots(2, 1, gridspec_kw={'height_ratios': [1, 2]})

C. plt.subplots(1, 2, gridspec_kw={'height_ratios': [2, 1]})

D. plt.subplots(2, 1, gridspec_kw={'width_ratios': [1, 2]})

Solution

1. Step 1: Identify correct parameter for horizontal subplots

   For 1 row and 2 columns, use 'width_ratios' to set horizontal size ratios.

2. Step 2: Match ratios to subplot layout

   plt.subplots(1, 2, gridspec_kw={'width_ratios': [2, 1]}) uses 1 row, 2 columns with width_ratios, which is correct syntax.

3. Final Answer:

   plt.subplots(1, 2, gridspec_kw={'width_ratios': [2, 1]}) -> Option A

4. Quick Check:

   Width ratios for columns = plt.subplots(1, 2, gridspec_kw={'width_ratios': [2, 1]}) [OK]

Hint: Use width_ratios for columns, height_ratios for rows [OK]

Common Mistakes:

• Mixing width_ratios with rows instead of columns
• Using height_ratios for horizontal layout
• Wrong number of rows and columns in function

3. What will be the width ratio of the two subplots created by this code?

fig, axs = plt.subplots(1, 2, gridspec_kw={'width_ratios': [3, 1]})

medium

A. Both subplots have equal width

B. The subplots have random widths

C. The second subplot is 3 times wider than the first

D. The first subplot is 3 times wider than the second

Solution

1. Step 1: Understand width_ratios parameter

   The list [3, 1] means the first subplot width is 3 units, second is 1 unit.

2. Step 2: Interpret ratio meaning

   This means the first subplot is 3 times wider than the second subplot.

3. Final Answer:

   The first subplot is 3 times wider than the second -> Option D

4. Quick Check:

   Width ratio 3:1 means first is 3x wider [OK]

Hint: Ratio list directly shows relative sizes [OK]

Common Mistakes:

• Assuming equal widths despite ratios
• Reversing which subplot is wider
• Ignoring the ratio values

4. Identify the error in this code that tries to create unequal subplot sizes:

fig, axs = plt.subplots(2, 1, gridspec_kw={'width_ratios': [1, 2]})

medium

A. Incorrect number of subplots specified

B. Using width_ratios for vertical subplots instead of height_ratios

C. Missing plt.show() to display plots

D. width_ratios list length does not match subplot count

Solution

1. Step 1: Check subplot layout

   2 rows and 1 column means vertical stacking of subplots.

2. Step 2: Verify correct ratio parameter

   For vertical layout, use 'height_ratios', not 'width_ratios'.

3. Final Answer:

   Using width_ratios for vertical subplots instead of height_ratios -> Option B

4. Quick Check:

   Vertical layout needs height_ratios [OK]

Hint: Use height_ratios for rows, width_ratios for columns [OK]

Common Mistakes:

• Confusing width_ratios and height_ratios
• Ignoring subplot grid shape
• Assuming plt.show() affects subplot sizes

5. You want to create a figure with 3 subplots in one row where the middle subplot is twice as wide as the others. Which code correctly achieves this?

hard

A. plt.subplots(1, 3, gridspec_kw={'width_ratios': [1, 2, 1]})

B. plt.subplots(3, 1, gridspec_kw={'height_ratios': [1, 2, 1]})

C. plt.subplots(1, 3, gridspec_kw={'height_ratios': [1, 2, 1]})

D. plt.subplots(3, 1, gridspec_kw={'width_ratios': [1, 2, 1]})

Solution

1. Step 1: Determine subplot layout

   One row and three columns means horizontal layout.

2. Step 2: Choose correct ratio parameter

   For horizontal layout, use 'width_ratios' to set widths.

3. Step 3: Set ratios to make middle subplot twice as wide

   Use [1, 2, 1] so middle subplot is twice the width of others.

4. Final Answer:

   plt.subplots(1, 3, gridspec_kw={'width_ratios': [1, 2, 1]}) -> Option A

5. Quick Check:

   Horizontal layout with width_ratios = plt.subplots(1, 3, gridspec_kw={'width_ratios': [1, 2, 1]}) [OK]

Hint: Middle subplot twice wide = width_ratios [1, 2, 1] [OK]

Common Mistakes:

• Using height_ratios for horizontal layout
• Setting wrong number of rows and columns
• Reversing ratio order