Broken axes concept in Matplotlib - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of using broken axes in a plot?

Broken axes help to focus on important parts of data by skipping uninteresting ranges, making it easier to see details in different value ranges.

intermediate

How do you create broken axes in matplotlib?

You create broken axes by making multiple subplots with shared axes and hiding the parts you want to skip, then adding diagonal lines to show the break.

beginner

Why might broken axes be better than zooming in on a plot?

Broken axes show different parts of data at once without losing context, while zooming only shows one part and hides the rest.

beginner

Which matplotlib function is commonly used to create subplots for broken axes?

The function plt.subplots() is commonly used to create multiple axes for broken axes plots.

beginner

What visual cue is often added to broken axes to indicate the break?

Diagonal lines or zigzag marks are added on the axes to show where the axis is broken.

What does a broken axis help you do in a plot?

A Change the color of the plot

B Make the plot 3D

C Add grid lines automatically

D Skip unimportant data ranges to focus on key parts

Broken axes let you skip parts of the axis to focus on important data ranges.

Which matplotlib function is used to create multiple axes for broken axes?

A plt.subplots()

B plt.plot()

C plt.scatter()

D plt.hist()

plt.subplots() creates multiple axes needed for broken axes plots.

What visual element usually shows where the axis is broken?

A Diagonal lines

B Arrow

C Circle

D Dots

Diagonal lines or zigzag marks indicate the break in the axis.

Why might broken axes be preferred over zooming in on a plot?

A They remove axis labels

B They show multiple data ranges at once

C They add animation

D They change the plot color

Broken axes show different parts of data together without losing context.

What is a key step when creating broken axes in matplotlib?

A Adding a legend

B Changing the figure size only

C Using multiple subplots and hiding parts of axes

D Using plt.scatter()

Creating broken axes involves multiple subplots and hiding axis parts to skip ranges.

Explain how broken axes help in visualizing data and describe the steps to create them in matplotlib.

Think about how to show important data ranges clearly by skipping others.

Describe the visual cues used in broken axes plots and why they are important.

Consider how to signal to the viewer that the axis is not continuous.

Practice

1. What is the main purpose of using broken axes in matplotlib plots?

easy

A. To skip unimportant data ranges and focus on key parts

B. To add 3D effects to the plot

C. To change the color scheme automatically

D. To animate the plot over time

Solution

1. Step 1: Understand the concept of broken axes

   Broken axes are used to skip over parts of the axis where data is not important or has large gaps.

2. Step 2: Identify the main purpose

   This helps to focus on important data ranges without showing the entire axis continuously.

3. Final Answer:

   To skip unimportant data ranges and focus on key parts -> Option A

4. Quick Check:

   Broken axes = skip gaps [OK]

Hint: Broken axes hide gaps to highlight important data [OK]

Common Mistakes:

• Thinking broken axes add 3D or animation
• Confusing broken axes with color changes
• Assuming broken axes zoom in automatically

2. Which of the following is the correct way to import the brokenaxes package to use brokenaxes(...) directly for creating broken axes plots?

easy

A. from brokenaxes import BrokenAxes

B. import brokenaxes as ba

C. from brokenaxes import brokenaxes

D. import matplotlib.brokenaxes as ba

Solution

1. Step 1: Recall the correct import syntax

   The brokenaxes package provides the brokenaxes function to create broken axes plots.

2. Step 2: Identify the correct import statement

   The correct way is from brokenaxes import brokenaxes to access the function directly.

3. Final Answer:

   from brokenaxes import brokenaxes -> Option C

4. Quick Check:

   Import brokenaxes function = from brokenaxes import brokenaxes [OK]

Hint: Import brokenaxes function directly from brokenaxes [OK]

Common Mistakes:

• Using capital 'BrokenAxes' instead of 'brokenaxes'
• Trying to import from matplotlib instead of brokenaxes
• Using wrong import syntax causing ImportError

3. What will the following code output?

from brokenaxes import brokenaxes
import matplotlib.pyplot as plt

bax = brokenaxes(ylims=((0, 2), (8, 10)))
bax.plot([0, 1, 2, 3], [1, 1.5, 9, 9.5])
plt.show()

medium

A. A plot with y-axis broken between 2 and 8 showing points near 1 and 9

B. A plot with continuous y-axis from 0 to 10

C. An error because ylims must be a single tuple

D. A plot with x-axis broken between 2 and 8

Solution

1. Step 1: Analyze the ylims parameter

   The ylims=((0, 2), (8, 10)) means the y-axis is broken to show two ranges: 0 to 2 and 8 to 10, skipping 2 to 8.

2. Step 2: Understand the plotted points

   The y-values are 1, 1.5, 9, and 9.5, which fit into the two visible y-axis ranges.

3. Final Answer:

   A plot with y-axis broken between 2 and 8 showing points near 1 and 9 -> Option A

4. Quick Check:

   ylims tuple of ranges = broken y-axis [OK]

Hint: ylims with tuples creates breaks on y-axis [OK]

Common Mistakes:

• Assuming y-axis is continuous without breaks
• Confusing x-axis and y-axis breaks
• Expecting an error from tuple ylims

4. Identify the error in this code snippet that tries to create broken axes:

from brokenaxes import brokenaxes
import matplotlib.pyplot as plt

bax = brokenaxes(xlims=(0, 2), (5, 7))
bax.plot([1, 6], [10, 20])
plt.show()

medium

A. plt.show() must be called before plot

B. plot function requires x and y to be the same length

C. BrokenAxes cannot be used with xlims parameter

D. xlims should be a tuple of tuples, not separate tuples

Solution

1. Step 1: Check the xlims argument syntax

   The code uses xlims=(0, 2), (5, 7) which is invalid syntax; it should be a single tuple containing tuples like xlims=((0, 2), (5, 7)).

2. Step 2: Confirm other parts are correct

   The plot call and plt.show() are correct; the error is only in xlims syntax.

3. Final Answer:

   xlims should be a tuple of tuples, not separate tuples -> Option D

4. Quick Check:

   xlims syntax = tuple of tuples [OK]

Hint: Use double parentheses for xlims tuple of ranges [OK]

Common Mistakes:

• Passing multiple tuples without enclosing in one tuple
• Mixing up xlims and ylims syntax
• Calling plt.show() too early

5. You have data with y-values clustered around 0-3 and 50-55, with a large gap in between. How would you create a broken y-axis to show both clusters clearly using brokenaxes?

hard

A. Plot two separate figures for each cluster

B. Use ylims=((0, 3), (50, 55)) when creating brokenaxes

C. Use xlims=((0, 3), (50, 55)) to break x-axis instead

D. Use ylims=(0, 55) to show full range without breaks

Solution

1. Step 1: Identify the axis to break

   The gap is in y-values, so the y-axis needs to be broken to skip the large gap between 3 and 50.

2. Step 2: Set ylims with two ranges

   Using ylims=((0, 3), (50, 55)) creates a broken y-axis showing both clusters clearly.

3. Final Answer:

   Use ylims=((0, 3), (50, 55)) when creating brokenaxes -> Option B

4. Quick Check:

   Broken y-axis = ylims tuple of ranges [OK]

Hint: Set ylims with two ranges to break y-axis gaps [OK]

Common Mistakes:

• Breaking x-axis instead of y-axis
• Using single continuous ylims hiding gap
• Plotting separate figures unnecessarily