Subplot spacing adjustment in Matplotlib - Step-by-Step Execution

Concept Flow - Subplot spacing adjustment

Create figure and subplots

↓

Plot data on each subplot

↓

Adjust spacing parameters

↓

Render figure with new spacing

↓

Display or save figure

This flow shows creating subplots, plotting data, adjusting spacing between them, and then displaying the figure.

Execution Sample

Matplotlib

import matplotlib.pyplot as plt
fig, axs = plt.subplots(2, 2)
fig.subplots_adjust(hspace=0.5, wspace=0.3)
axs[0,0].plot([1,2,3], [1,4,9])
plt.show()

Creates a 2x2 grid of plots, adjusts vertical and horizontal spacing, plots data on top-left subplot, then shows the figure.

Execution Table

Step	Action	Parameter Changed	Value	Effect on Layout
1	Create figure and 2x2 subplots	None	None	4 subplots arranged in 2 rows and 2 columns with default spacing
2	Adjust vertical spacing (hspace)	hspace	0.5	Increases vertical space between rows
3	Adjust horizontal spacing (wspace)	wspace	0.3	Increases horizontal space between columns
4	Plot data on axs[0,0]	None	None	Data plotted on top-left subplot
5	Render and display figure	None	None	Figure shown with adjusted subplot spacing

💡 All steps complete, figure displayed with new subplot spacing

Variable Tracker

Variable	Start	After Step 1	After Step 2	After Step 3	Final
fig	None	Figure with 4 subplots	Figure with adjusted hspace=0.5	Figure with adjusted wspace=0.3	Final figure ready to display
axs	None	2x2 array of Axes objects	Unchanged	Unchanged	Unchanged

Key Moments - 2 Insights

Why do we need to call fig.subplots_adjust after creating subplots?

Because default subplot spacing can be too tight, fig.subplots_adjust lets us increase space between plots to avoid overlap, as shown in steps 2 and 3 in the execution_table.

What happens if we set hspace or wspace to 0?

Subplots will have no space between rows or columns, causing axes labels or titles to overlap, which is why positive values like 0.5 or 0.3 are used in steps 2 and 3.

Visual Quiz - 3 Questions

Look at the execution_table, what is the value of wspace after step 3?

A 0.5

B Default (usually 0.2)

C 0.3

D 1.0

💡 Hint

Check the 'Parameter Changed' and 'Value' columns at step 3 in execution_table.

At which step is data plotted on the top-left subplot?

A Step 4

B Step 2

C Step 1

D Step 5

💡 Hint

Look at the 'Action' column in execution_table for when plotting occurs.

If we set hspace to 0, how would the layout effect change compared to step 2?

A More vertical space between rows

B No vertical space between rows

C More horizontal space between columns

D No horizontal space between columns

💡 Hint

Refer to the 'Effect on Layout' column for hspace in execution_table step 2.

Concept Snapshot

Subplot spacing adjustment:
- Use fig.subplots_adjust(hspace=val, wspace=val)
- hspace controls vertical space between rows
- wspace controls horizontal space between columns
- Default spacing may cause overlap
- Adjust before plt.show() to see effect

Full Transcript

This visual execution shows how to adjust spacing between subplots in matplotlib. First, we create a figure with a 2x2 grid of subplots. Then, we increase vertical spacing using hspace=0.5 and horizontal spacing using wspace=0.3 with fig.subplots_adjust. Next, we plot data on the top-left subplot. Finally, we render and display the figure with the new spacing. Adjusting subplot spacing helps prevent overlapping labels and makes the figure clearer.

Practice

1. What does the plt.subplots_adjust() function do in matplotlib?

easy

A. It changes the space between subplots in a figure.

B. It creates new subplots in a figure.

C. It saves the figure to a file.

D. It changes the color of the plot lines.

Solution

1. Step 1: Understand the purpose of plt.subplots_adjust()

   This function is used to control the spacing between subplots in a matplotlib figure.

2. Step 2: Compare options

   Only It changes the space between subplots in a figure. correctly describes adjusting space between subplots. Other options describe different functions.

3. Final Answer:

   It changes the space between subplots in a figure. -> Option A

4. Quick Check:

   Subplot spacing adjustment = plt.subplots_adjust() [OK]

Hint: Remember: adjust spacing, not create or save plots [OK]

Common Mistakes:

• Confusing subplot creation with spacing adjustment
• Thinking it saves the figure
• Mixing it with styling functions

2. Which of the following is the correct syntax to increase horizontal space between subplots using plt.subplots_adjust()?

easy

A. plt.subplots_adjust(hspace=0.5)

B. plt.subplots_adjust(space=0.5)

C. plt.subplots_adjust(wspace=0.5)

D. plt.subplots_adjust(widthspace=0.5)

Solution

1. Step 1: Identify parameter for horizontal spacing

   The parameter wspace controls horizontal space between subplots.

2. Step 2: Check syntax correctness

   plt.subplots_adjust(wspace=0.5) uses wspace=0.5, which is correct. Other options use incorrect or non-existent parameters.

3. Final Answer:

   plt.subplots_adjust(wspace=0.5) -> Option C

4. Quick Check:

   wspace adjusts horizontal space [OK]

Hint: Use wspace for width (horizontal), hspace for height (vertical) [OK]

Common Mistakes:

• Using hspace instead of wspace for horizontal spacing
• Using wrong parameter names like space or widthspace
• Syntax errors in function call

3. What will be the effect of this code on subplot spacing?

import matplotlib.pyplot as plt
fig, axs = plt.subplots(1, 2)
plt.subplots_adjust(wspace=1.0)
plt.show()

medium

A. Subplots will have increased horizontal space between them.

B. Subplots will be very close horizontally with almost no space.

C. Subplots will overlap each other.

D. Subplots will have increased vertical space between them.

Solution

1. Step 1: Understand wspace=1.0 effect

   Setting wspace to 1.0 increases horizontal space between subplots significantly.

2. Step 2: Analyze code behavior

   Since there are 2 subplots side by side, they will be spaced apart horizontally, not vertically.

3. Final Answer:

   Subplots will have increased horizontal space between them. -> Option A

4. Quick Check:

   wspace=1.0 means more horizontal space [OK]

Hint: wspace controls horizontal gap size between subplots [OK]

Common Mistakes:

• Confusing wspace with hspace
• Expecting subplots to overlap
• Thinking spacing affects vertical gap

4. Identify the error in this code that tries to adjust subplot spacing:

import matplotlib.pyplot as plt
fig, axs = plt.subplots(2, 1)
plt.subplots_adjust(wspace=0.3, hspace=0.5)
plt.show()

medium

A. Using hspace with vertical subplots is invalid.

B. Using wspace when subplots are stacked vertically.

C. Incorrect number of subplots created.

D. Missing plt.show() call.

Solution

1. Step 1: Analyze subplot layout

   The code creates 2 subplots stacked vertically (2 rows, 1 column).

2. Step 2: Check spacing parameters

   wspace controls horizontal spacing, which is irrelevant here because subplots are vertical. Only hspace affects vertical spacing.

3. Final Answer:

   Using wspace when subplots are stacked vertically. -> Option B

4. Quick Check:

   wspace for horizontal, not vertical spacing [OK]

Hint: Match wspace to horizontal, hspace to vertical layout [OK]

Common Mistakes:

• Using wspace for vertical subplot spacing
• Ignoring subplot grid shape
• Assuming hspace is invalid for vertical layout

5. You have a 2x2 grid of subplots with overlapping x-axis labels. Which plt.subplots_adjust() call best reduces overlap by increasing vertical space and adding some horizontal space?

hard

A. plt.subplots_adjust(wspace=1.5, hspace=0.0)

B. plt.subplots_adjust(wspace=0.0, hspace=0.0)

C. plt.subplots_adjust(wspace=0.0, hspace=1.5)

D. plt.subplots_adjust(wspace=0.4, hspace=0.6)

Solution

1. Step 1: Understand the problem of overlapping x-axis labels

   Overlapping x-axis labels usually happen vertically between rows, so increasing vertical space (hspace) helps.

2. Step 2: Consider horizontal space

   Adding some horizontal space (wspace) also improves readability between columns.

3. Step 3: Evaluate options

   plt.subplots_adjust(wspace=0.4, hspace=0.6) increases both wspace and hspace moderately, which best reduces overlap without wasting space.

4. Final Answer:

   plt.subplots_adjust(wspace=0.4, hspace=0.6) -> Option D

5. Quick Check:

   Increase hspace and wspace moderately to reduce overlap [OK]

Hint: Increase hspace for vertical gaps, wspace for horizontal gaps [OK]

Common Mistakes:

• Setting spacing to zero causing overlap
• Increasing only one spacing dimension
• Using too large spacing causing wasted space