Unequal subplot sizes in Matplotlib - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the main purpose of using unequal subplot sizes in matplotlib?

To allocate different amounts of space to each subplot, allowing some plots to be larger or smaller based on their importance or data detail.

beginner

Which matplotlib function helps create subplots with custom size ratios?

The gridspec module, especially GridSpec, allows you to define the relative sizes of rows and columns for subplots.

intermediate

How do you specify different height ratios for subplots in matplotlib?

Use GridSpec with the height_ratios parameter, passing a list of numbers that represent relative heights for each row.

intermediate

What is the difference between plt.subplot() and GridSpec when creating subplots?

plt.subplot() creates subplots with equal sizes by default, while GridSpec allows flexible control over subplot sizes and layout.

beginner

Show a simple code snippet to create two vertical subplots with the top subplot twice as tall as the bottom one.

import matplotlib.pyplot as plt
from matplotlib.gridspec import GridSpec

fig = plt.figure()
gs = GridSpec(2, 1, height_ratios=[2, 1])
ax1 = fig.add_subplot(gs[0, 0])
ax2 = fig.add_subplot(gs[1, 0])

ax1.plot([1, 2, 3], [1, 4, 9])
ax2.plot([1, 2, 3], [9, 4, 1])

plt.show()

Which matplotlib module allows you to create subplots with unequal sizes?

A pyplot.subplot

B GridSpec

C numpy

D pandas

GridSpec is the module designed for flexible subplot layouts including unequal sizes.

How do you control the relative height of subplots in a vertical layout?

A Using <code>height_ratios</code> in GridSpec

B Using <code>width_ratios</code> in GridSpec

C Using <code>plt.subplot()</code> only

D Using <code>plt.figure(figsize=)</code>

height_ratios sets relative heights for rows in GridSpec.

What happens if you do not specify size ratios when creating subplots?

A An error occurs

B Subplots have random sizes

C Only one subplot is shown

D All subplots have equal size

By default, subplots have equal sizes if no ratios are specified.

Which parameter would you use to make the left subplot wider than the right one in a horizontal layout?

A width_ratios

B height_ratios

C subplot_kw

D figsize

width_ratios controls relative widths of columns in GridSpec.

What is the benefit of using unequal subplot sizes?

A To make all plots look the same

B To reduce the number of plots

C To highlight important plots by giving them more space

D To change plot colors automatically

Unequal sizes help emphasize some plots by allocating more space.

Explain how to create vertical subplots with different heights using matplotlib.

Think about how to tell matplotlib to make one subplot taller than another.

Describe the difference between using plt.subplot() and GridSpec for subplot layouts.

Consider which method gives you more control over subplot sizes.

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