Major and minor ticks in Matplotlib - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set major ticks on the x-axis every 2 units.

Matplotlib

import matplotlib.pyplot as plt
from matplotlib.ticker import AutoLocator, FixedLocator, MaxNLocator, MultipleLocator
fig, ax = plt.subplots()
ax.plot([1, 2, 3, 4, 5])
ax.xaxis.set_major_locator([1](2))
plt.show()

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

AAutoLocator

BMaxNLocator

CFixedLocator

DMultipleLocator

Attempts:

3 left

💡 Hint

Common Mistakes

Using MaxNLocator which tries to choose a maximum number of ticks but not fixed intervals.

Using FixedLocator without specifying exact tick positions.

The MultipleLocator sets ticks at multiples of the given base, here 2.

2fill in blank

medium

Complete the code to set minor ticks on the y-axis every 0.5 units.

Matplotlib

import matplotlib.pyplot as plt
from matplotlib.ticker import AutoLocator, FixedLocator, MaxNLocator, MultipleLocator
fig, ax = plt.subplots()
ax.plot([0.1, 0.4, 0.9, 1.2, 1.8])
ax.yaxis.set_minor_locator([1](0.5))
plt.show()

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

AMultipleLocator

BMaxNLocator

CFixedLocator

DAutoLocator

Attempts:

3 left

💡 Hint

Common Mistakes

Using MaxNLocator which does not guarantee fixed intervals.

Not setting minor ticks locator at all.

MultipleLocator is used to set ticks at fixed intervals, here 0.5 for minor ticks.

3fill in blank

hard

Fix the error in the code to correctly set major ticks at 1, 3, and 5 on the x-axis.

Matplotlib

import matplotlib.pyplot as plt
from matplotlib.ticker import AutoLocator, FixedLocator, MaxNLocator, MultipleLocator
fig, ax = plt.subplots()
ax.plot([10, 20, 30, 40, 50])
ax.xaxis.set_major_locator([1]([1, 3, 5]))
plt.show()

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

AMultipleLocator

BFixedLocator

CMaxNLocator

DAutoLocator

Attempts:

3 left

💡 Hint

Common Mistakes

Using MultipleLocator which expects a single base number, not a list.

Using MaxNLocator which chooses ticks automatically.

FixedLocator is used to set ticks at specific positions given as a list.

4fill in blank

hard

Fill both blanks to set major ticks every 1 unit and minor ticks every 0.2 units on the y-axis.

Matplotlib

import matplotlib.pyplot as plt
from matplotlib.ticker import AutoLocator, FixedLocator, MaxNLocator, MultipleLocator
fig, ax = plt.subplots()
ax.plot([0, 1, 2, 3, 4])
ax.yaxis.set_major_locator([1](1))
ax.yaxis.set_minor_locator([2](0.2))
plt.show()

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

AMultipleLocator

BMaxNLocator

CFixedLocator

DAutoLocator

Attempts:

3 left

💡 Hint

Common Mistakes

Using different locator types for major and minor ticks.

Using MaxNLocator which does not guarantee fixed intervals.

MultipleLocator is used for both major and minor ticks to set fixed intervals.

5fill in blank

hard

Fill all three blanks to create a dictionary of minor tick positions for x-axis where keys are the tick positions and values are their squares, but only for ticks greater than 2.

Matplotlib

import matplotlib.pyplot as plt
from matplotlib.ticker import AutoLocator, FixedLocator, MaxNLocator, MultipleLocator
fig, ax = plt.subplots()
ax.xaxis.set_minor_locator(MultipleLocator(1))
minor_ticks = { [1] : [2] for [3] in ax.xaxis.get_minor_locator().tick_values(0, 5) if [3] > 2 }
print(minor_ticks)

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

Atick

Btick**2

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names inconsistently.

Not squaring the tick values for dictionary values.

The dictionary comprehension uses tick as the key and tick**2 as the value, iterating over minor tick positions.

Practice

1. What is the main purpose of major ticks in a matplotlib plot?

easy

A. To change the color of the plot

B. To add grid lines to the plot

C. To label the plot title

D. To mark the main points on the axes

Solution

1. Step 1: Understand the role of major ticks

   Major ticks are the primary markers on the axes that show key values.

2. Step 2: Differentiate from other elements

   Grid lines and titles are different plot features, not related to major ticks.

3. Final Answer:

   To mark the main points on the axes -> Option D

4. Quick Check:

   Major ticks = main axis points [OK]

Hint: Major ticks show main axis points clearly [OK]

Common Mistakes:

• Confusing major ticks with grid lines
• Thinking major ticks change plot colors
• Mixing up ticks with plot titles

2. Which of the following is the correct way to set minor ticks on the x-axis using matplotlib?

easy

A. plt.minorticks_on()

B. plt.set_minor_ticks()

C. plt.minor_ticks()

D. plt.set_minor()

Solution

1. Step 1: Recall matplotlib minor ticks method

   The correct method to enable minor ticks is plt.minorticks_on().

2. Step 2: Check other options

   Other options are not valid matplotlib functions and will cause errors.

3. Final Answer:

   plt.minorticks_on() -> Option A

4. Quick Check:

   Enable minor ticks = plt.minorticks_on() [OK]

Hint: Use plt.minorticks_on() to enable minor ticks [OK]

Common Mistakes:

• Using non-existent functions like plt.set_minor_ticks()
• Confusing minor ticks enabling with setting labels
• Forgetting to call the function

3. What will be the effect of this code snippet?

import matplotlib.pyplot as plt
from matplotlib.ticker import MultipleLocator
fig, ax = plt.subplots()
ax.plot([1, 2, 3, 4])
ax.xaxis.set_major_locator(MultipleLocator(2))
ax.xaxis.set_minor_locator(MultipleLocator(0.5))
ax.minorticks_on()
plt.show()

medium

A. Major ticks every 2 units, minor ticks every 0.5 units on x-axis

B. Major ticks every 0.5 units, minor ticks every 2 units on x-axis

C. Only major ticks at 1 and 3, no minor ticks

D. Syntax error due to wrong locator usage

Solution

1. Step 1: Analyze major locator setting

   Major ticks are set every 2 units on the x-axis using MultipleLocator(2).

2. Step 2: Analyze minor locator setting

   Minor ticks are set every 0.5 units using MultipleLocator(0.5).

3. Final Answer:

   Major ticks every 2 units, minor ticks every 0.5 units on x-axis -> Option A

4. Quick Check:

   Major=2, Minor=0.5 units [OK]

Hint: Major locator sets big steps, minor locator sets small steps [OK]

Common Mistakes:

• Swapping major and minor locator values
• Assuming no minor ticks appear without plt.minorticks_on()
• Thinking locator causes syntax error

4. Identify the error in this code that tries to set minor ticks:

import matplotlib.pyplot as plt
from matplotlib.ticker import MultipleLocator
fig, ax = plt.subplots()
ax.plot([10, 20, 30])
ax.xaxis.set_minor_locator(MultipleLocator(1))
plt.minorticks_on()
plt.show()

medium

A. plt.minorticks_on() should be called on ax, not plt

B. No error, code runs fine

C. Missing plt.show() call

D. MultipleLocator cannot be used for minor ticks

Solution

1. Step 1: Check locator and import

   MultipleLocator is correctly used for minor ticks with proper import from matplotlib.ticker.

2. Step 2: Verify minorticks_on()

   plt.minorticks_on() works after plt.subplots() as it applies to the current axes object.

3. Final Answer:

   No error, code runs fine -> Option B

4. Quick Check:

   plt.minorticks_on() works with ax [OK]

Hint: plt.minorticks_on() works even with explicit axes objects [OK]

Common Mistakes:

• Not importing MultipleLocator from matplotlib.ticker
• Thinking MultipleLocator cannot be used for minor ticks
• Forgetting to call plt.show()

5. You want to create a plot with major ticks every 5 units and minor ticks every 1 unit on the y-axis only. Which code snippet correctly achieves this?

hard

A. ax.yaxis.set_major_locator(MultipleLocator(1))
ax.yaxis.set_minor_locator(MultipleLocator(5))
plt.minorticks_on()

B. ax.xaxis.set_major_locator(MultipleLocator(5))
ax.xaxis.set_minor_locator(MultipleLocator(1))
ax.minorticks_on()

C. ax.yaxis.set_major_locator(MultipleLocator(5))
ax.yaxis.set_minor_locator(MultipleLocator(1))
ax.minorticks_on()

D. ax.yaxis.set_major_locator(MultipleLocator(5))
ax.yaxis.set_minor_locator(MultipleLocator(1))
plt.minorticks_off()

Solution

1. Step 1: Set major and minor locators on y-axis

   Major ticks every 5 units and minor ticks every 1 unit require ax.yaxis.set_major_locator(MultipleLocator(5)) and ax.yaxis.set_minor_locator(MultipleLocator(1)).

2. Step 2: Enable minor ticks on the axes object

   Use ax.minorticks_on() to show minor ticks on the axes.

3. Final Answer:

   ax.yaxis.set_major_locator(MultipleLocator(5)) ax.yaxis.set_minor_locator(MultipleLocator(1)) ax.minorticks_on() -> Option C

4. Quick Check:

   Major=5, Minor=1 on y-axis with ax.minorticks_on() [OK]

Hint: Set locators on yaxis and call ax.minorticks_on() [OK]

Common Mistakes:

• Setting locators on x-axis instead of y-axis
• Calling plt.minorticks_on() instead of ax.minorticks_on()
• Swapping major and minor locator values