Multi-line text in Matplotlib - Mini Project: Build & Apply

Adding Multi-line Text to a Matplotlib Plot

📖 Scenario: You are creating a simple plot to show sales data for two products. You want to add a multi-line text note on the plot to explain the data.

🎯 Goal: Build a plot with two lines and add a multi-line text annotation inside the plot area.

📋 What You'll Learn

Create a plot with two lines representing sales data.

Add a multi-line text note inside the plot using plt.text.

Use newline characters \n to create multiple lines in the text.

💡 Why This Matters

🌍 Real World

Adding multi-line text notes on plots helps explain data clearly in reports and presentations.

💼 Career

Data scientists and analysts often annotate plots with multi-line text to highlight insights or provide context.

1

Create sales data lists

Create two lists called sales_product_a and sales_product_b with these exact values: [10, 15, 20, 25] and [12, 18, 22, 28] respectively.

Matplotlib

# Create sales data lists
# Your code here

Hint

Use square brackets to create lists with the exact numbers given.

2

Create x-axis values

Create a list called months with these exact values: [1, 2, 3, 4] representing four months.

Matplotlib

sales_product_a = [10, 15, 20, 25]
sales_product_b = [12, 18, 22, 28]
# Create months list
# Your code here

Hint

Use a list with the numbers 1 to 4 for months.

3

Plot the sales data lines

Import matplotlib.pyplot as plt. Use plt.plot to plot months vs sales_product_a and months vs sales_product_b. Add labels 'Product A' and 'Product B' respectively.

Matplotlib

sales_product_a = [10, 15, 20, 25]
sales_product_b = [12, 18, 22, 28]
months = [1, 2, 3, 4]
# Import matplotlib.pyplot as plt
# Plot sales_product_a and sales_product_b against months with labels
# Your code here

Hint

Use plt.plot(x, y, label='name') to plot lines with labels.

4

Add multi-line text and show plot

Use plt.text to add multi-line text at position (2, 15) with the exact text: 'Sales Data\nProduct A and B'. Then add plt.legend() and plt.show() to display the plot.

Matplotlib

import matplotlib.pyplot as plt

sales_product_a = [10, 15, 20, 25]
sales_product_b = [12, 18, 22, 28]
months = [1, 2, 3, 4]

plt.plot(months, sales_product_a, label='Product A')
plt.plot(months, sales_product_b, label='Product B')
# Add multi-line text at (2, 15) with 'Sales Data\nProduct A and B'
# Add legend and show the plot
# Your code here

Hint

Use plt.text(x, y, 'line1\nline2') to add multi-line text.

Practice

1. What does the \n character do inside a text string in matplotlib?

easy

A. It adds a space between words.

B. It changes the text color.

C. It creates a new line, splitting the text into multiple lines.

D. It makes the text bold.

Solution

1. Step 1: Understand the role of \n in strings

   The \n character is a newline character that breaks text into multiple lines.

2. Step 2: Apply this to matplotlib text

   Using \n inside a string in matplotlib text splits the text into separate lines on the plot.

3. Final Answer:

   It creates a new line, splitting the text into multiple lines. -> Option C

4. Quick Check:

   Newline character = creates new line [OK]

Hint: Remember \n means new line inside text strings [OK]

Common Mistakes:

• Thinking \n adds space instead of new line
• Confusing \n with color or style commands
• Using \n outside text strings

2. Which of the following is the correct way to add multi-line text at position (2, 3) in a matplotlib plot?

easy

A. plt.text(2, 3, 'Line1\nLine2')

B. plt.text('2, 3', 'Line1\nLine2')

C. plt.text(2, 3, 'Line1\Line2')

D. plt.text(2, 3, 'Line1/Line2')

Solution

1. Step 1: Check the syntax of plt.text()

   The function plt.text(x, y, text) requires numeric x and y coordinates and a string for text.

2. Step 2: Identify the newline character

   The newline character is \n, so 'Line1\nLine2' correctly creates two lines.

3. Final Answer:

   plt.text(2, 3, 'Line1\nLine2') -> Option A

4. Quick Check:

   Correct syntax with \n = plt.text(2, 3, 'Line1\nLine2') [OK]

Hint: Use plt.text(x, y, 'line1\nline2') for multi-line text [OK]

Common Mistakes:

• Passing coordinates as a string instead of numbers
• Using wrong escape characters like \ or /
• Missing the newline character \n

3. What will the following code display on the plot?

import matplotlib.pyplot as plt
plt.plot([1, 2, 3], [4, 5, 6])
plt.text(2, 5, 'Hello\nWorld', fontsize=12, color='red')
plt.show()

medium

A. A plot with red text 'Hello' on one line and 'World' below it at position (2,5).

B. A plot with red text 'Hello World' on a single line at position (2,5).

C. A plot with blue text 'Hello\nWorld' at position (2,5).

D. A plot with no text displayed.

Solution

1. Step 1: Understand plt.text parameters

   The text is placed at (2,5) with font size 12 and color red. The string contains a newline \n.

2. Step 2: Interpret the newline in text

   The \n splits 'Hello' and 'World' into two lines, so text appears as two lines stacked vertically.

3. Final Answer:

   A plot with red text 'Hello' on one line and 'World' below it at position (2,5). -> Option A

4. Quick Check:

   \n splits lines, color='red' applies [OK]

Hint: Look for \n to split lines and color param for text color [OK]

Common Mistakes:

• Ignoring the newline and expecting one line
• Confusing color red with blue
• Thinking text won't appear without plt.show()

4. Identify the error in this code snippet that tries to add multi-line text:

plt.text(1, 2, 'Line1\Line2', fontsize=10)

medium

A. The text string is missing quotes.

B. The fontsize parameter is invalid.

C. The coordinates (1, 2) are out of plot range.

D. The newline character is incorrect; it should be '\n' not '\'.

Solution

1. Step 1: Check the newline character usage

   The code uses '\' instead of '\n' to create a new line, which is incorrect.

2. Step 2: Confirm other parameters

   Fontsize is valid, coordinates are numeric, and text is quoted properly.

3. Final Answer:

   The newline character is incorrect; it should be '\n' not '\'. -> Option D

4. Quick Check:

   Use \n for new lines, not single backslash [OK]

Hint: Newline must be \n, not just \ alone [OK]

Common Mistakes:

• Using single backslash instead of \n
• Assuming fontsize causes error
• Thinking coordinates must be strings

5. You want to add a multi-line label on a plot at (0.5, 0.5) with the text:
"Temperature:\nHigh: 30°C\nLow: 15°C"
and make sure the text is centered and blue. Which code snippet achieves this?

hard

A. plt.text(0.5, 0.5, 'Temperature:\nHigh: 30°C\nLow: 15°C', fontsize=14, ha='center')

B. plt.text(0.5, 0.5, 'Temperature:\nHigh: 30°C\nLow: 15°C', color='blue', fontsize=14, ha='center')

C. plt.text(0.5, 0.5, 'Temperature\nHigh: 30°C\nLow: 15°C', color='red', fontsize=14, ha='left')

D. plt.text(0.5, 0.5, 'Temperature\nHigh: 30°C\nLow: 15°C', color='blue', fontsize=10, ha='right')

Solution

1. Step 1: Check the text string for new lines

   The text uses '\n' correctly to create multiple lines.

2. Step 2: Verify color, font size, and alignment

   Color is blue, fontsize is 14, and horizontal alignment (ha) is 'center' as required.

3. Final Answer:

   plt.text(0.5, 0.5, 'Temperature:\nHigh: 30°C\nLow: 15°C', color='blue', fontsize=14, ha='center') -> Option B

4. Quick Check:

   Correct text, color blue, center align = plt.text(0.5, 0.5, 'Temperature:\nHigh: 30°C\nLow: 15°C', color='blue', fontsize=14, ha='center') [OK]

Hint: Use ha='center' and color='blue' for centered blue multi-line text [OK]

Common Mistakes:

• Using wrong color or alignment
• Missing \n for new lines
• Setting fontsize too small or default