Label, title, and axis names in Matplotlib - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the title() function in matplotlib?

The title() function adds a title to the top of the plot, helping to explain what the plot is about.

beginner

How do you add a label to the x-axis in a matplotlib plot?

Use the xlabel() function with a string argument to name the x-axis, like plt.xlabel('Time (seconds)').

beginner

Which matplotlib function is used to label the y-axis?

The ylabel() function is used to add a label to the y-axis, for example plt.ylabel('Temperature (°C)').

beginner

Why is it important to add labels and titles to your plots?

Labels and titles make plots easier to understand by explaining what data is shown and what each axis represents, just like signs help you understand a map.

beginner

Show the matplotlib code to create a plot with title 'Sales Over Time', x-axis label 'Month', and y-axis label 'Sales ($)'.

import matplotlib.pyplot as plt
plt.plot([1, 2, 3, 4], [10, 20, 25, 30])
plt.title('Sales Over Time')
plt.xlabel('Month')
plt.ylabel('Sales ($)')
plt.show()

Which function adds a title to a matplotlib plot?

A title()

B xlabel()

C ylabel()

D legend()

The title() function sets the title of the plot.

How do you label the y-axis in matplotlib?

A ylabel()

B xlabel()

C title()

D plot()

Use ylabel() to add a label to the y-axis.

What does xlabel('Time') do in a plot?

A Labels the y-axis as 'Time'

B Creates a legend named 'Time'

C Adds a title 'Time'

D Labels the x-axis as 'Time'

xlabel() sets the label for the x-axis.

Why should you add axis labels to a plot?

A To save the plot

B To change the plot color

C To explain what each axis represents

D To add grid lines

Axis labels help viewers understand the data shown on each axis.

Which of these is NOT a function to add text labels in matplotlib?

A title()

B plot()

C xlabel()

D ylabel()

plot() draws data points; it does not add text labels.

Explain how to add a title and axis labels to a matplotlib plot and why it is useful.

Think about how titles and labels help someone reading your plot.

Write a short matplotlib code snippet that creates a simple line plot with a title and labels for both axes.

Start with plotting data, then add title and labels, finally show the plot.

Practice

1. Which matplotlib function is used to add a title to a plot?

easy

A. plt.label()

B. plt.title()

C. plt.name()

D. plt.head()

Solution

1. Step 1: Understand the purpose of each function

   plt.title() is designed to add a title to the plot, while the others do not exist or serve this purpose.

2. Step 2: Confirm the correct function for title

   The function plt.title() correctly adds a title to the plot.

3. Final Answer:

   plt.title() -> Option B

4. Quick Check:

   Title function = plt.title() [OK]

Hint: Title your plot with plt.title() for clarity [OK]

Common Mistakes:

• Using plt.label() instead of plt.title()
• Confusing axis labels with title
• Trying plt.name() which doesn't exist

2. Which of the following is the correct syntax to label the x-axis as 'Time (s)' in matplotlib?

easy

A. plt.axislabel('Time (s)')

B. plt.xaxis('Time (s)')

C. plt.labelx('Time (s)')

D. plt.xlabel('Time (s)')

Solution

1. Step 1: Recall the correct function for x-axis label

   The function to label the x-axis is plt.xlabel().

2. Step 2: Check syntax correctness

   plt.xlabel('Time (s)') uses the correct function and syntax: plt.xlabel('Time (s)').

3. Final Answer:

   plt.xlabel('Time (s)') -> Option D

4. Quick Check:

   X-axis label = plt.xlabel() [OK]

Hint: Use plt.xlabel() to name the x-axis quickly [OK]

Common Mistakes:

• Using plt.xaxis() which does not label axis
• Trying plt.labelx() which is invalid
• Confusing axis label with axis limits

3. What will be the output of the following code?

import matplotlib.pyplot as plt
plt.plot([1, 2, 3], [4, 5, 6])
plt.title('Sales Over Time')
plt.xlabel('Month')
plt.ylabel('Sales')
plt.show()

medium

A. A plot with title but no axis labels

B. A plot with no title and no axis labels

C. A plot with title 'Sales Over Time', x-axis labeled 'Month', and y-axis labeled 'Sales'

D. A plot with axis labels but no title

Solution

1. Step 1: Analyze the code for title and labels

   The code uses plt.title('Sales Over Time'), plt.xlabel('Month'), and plt.ylabel('Sales') to add title and axis labels.

2. Step 2: Understand the plot output

   The plot will display the line graph with the specified title and axis labels visible.

3. Final Answer:

   A plot with title 'Sales Over Time', x-axis labeled 'Month', and y-axis labeled 'Sales' -> Option C

4. Quick Check:

   Title and labels set = A plot with title 'Sales Over Time', x-axis labeled 'Month', and y-axis labeled 'Sales' [OK]

Hint: Check plt.title(), plt.xlabel(), plt.ylabel() for labels [OK]

Common Mistakes:

• Assuming labels won't show without plt.legend()
• Forgetting plt.show() to display plot
• Confusing axis labels with tick labels

4. Identify the error in this code snippet:

import matplotlib.pyplot as plt
plt.plot([1, 2, 3], [3, 2, 1])
plt.title = 'My Plot'
plt.xlabel('X Axis')
plt.ylabel('Y Axis')
plt.show()

medium

A. Incorrect assignment to plt.title instead of calling plt.title()

B. plt.xlabel() is missing parentheses

C. plt.plot() has wrong data format

D. plt.show() is missing

Solution

1. Step 1: Check how title is set

   The code uses plt.title = 'My Plot', which assigns a string to the function name, breaking it.

2. Step 2: Correct way to set title

   The correct syntax is to call the function: plt.title('My Plot').

3. Final Answer:

   Incorrect assignment to plt.title instead of calling plt.title() -> Option A

4. Quick Check:

   Title must be set by plt.title() function call [OK]

Hint: Use plt.title('text'), not plt.title = 'text' [OK]

Common Mistakes:

• Assigning string to plt.title instead of calling it
• Forgetting parentheses on function calls
• Confusing plt.title with plt.xlabel

5. You want to create a plot with the title 'Temperature Trends', x-axis labeled 'Day', and y-axis labeled 'Temperature (°C)'. Which code snippet correctly does this and also sets the font size of the title to 16?

hard

A. plt.title('Temperature Trends', fontsize=16)\nplt.xlabel('Day')\nplt.ylabel('Temperature (°C)')

B. plt.title('Temperature Trends')\nplt.xlabel('Day', fontsize=16)\nplt.ylabel('Temperature (°C)')

C. plt.title('Temperature Trends', size=16)\nplt.xlabel('Day')\nplt.ylabel('Temperature (°C)')

D. plt.title('Temperature Trends')\nplt.xlabel('Day')\nplt.ylabel('Temperature (°C)', fontsize=16)

Solution

1. Step 1: Identify how to set title font size

   The fontsize parameter in plt.title() sets the title font size correctly.

2. Step 2: Check axis labels and font size

   Only the title should have font size 16; axis labels do not need it here.

3. Final Answer:

   plt.title('Temperature Trends', fontsize=16) plt.xlabel('Day') plt.ylabel('Temperature (°C)') -> Option A

4. Quick Check:

   Title font size set by fontsize=16 in plt.title() [OK]

Hint: Use fontsize=16 inside plt.title() to resize title text [OK]

Common Mistakes:

• Using size=16 instead of fontsize=16
• Setting fontsize on axis labels instead of title
• Forgetting to call plt.title() as a function