Multi-line text in Matplotlib - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this multi-line text plot code?

Consider the following Python code using matplotlib. What will be the text displayed on the plot?

Matplotlib

import matplotlib.pyplot as plt

fig, ax = plt.subplots()
text = "Line 1\nLine 2\nLine 3"
ax.text(0.5, 0.5, text, ha='center', va='center')
plt.show()

A The plot shows three lines of text stacked vertically: 'Line 1', 'Line 2', and 'Line 3' centered on the plot.

B The plot shows the text 'Line 1\nLine 2\nLine 3' as a single line with literal \n characters visible.

C The plot is empty because the text is not displayed without specifying a font size.

D The plot shows only 'Line 1' because matplotlib ignores newlines in text.

💡 Hint

Think about how matplotlib handles newline characters in text strings.

Matplotlib interprets the newline character \n as a line break, so the text is shown on multiple lines stacked vertically.

🔧 Debug

intermediate

Why does this multi-line text not display correctly?

Look at this code snippet:

import matplotlib.pyplot as plt

fig, ax = plt.subplots()
text = 'First line\nSecond line\nThird line'
ax.text(0.5, 0.5, text, ha='center', va='center', wrap=True)
plt.show()

Why might the text not wrap or display as expected?

A Because the <code>wrap</code> parameter is not supported by <code>ax.text</code>, so it is ignored.

B Because the text string uses single quotes instead of double quotes, causing an error.

C Because the coordinates (0.5, 0.5) are outside the plot area, so text is not visible.

D Because the <code>ha</code> and <code>va</code> parameters must be set to 'left' and 'top' for multi-line text.

💡 Hint

Check the official documentation for ax.text parameters.

The wrap parameter is not a valid argument for ax.text. Newlines in the string handle line breaks, but wrapping long lines automatically is not supported here.

❓ visualization

advanced

Which option produces a plot with multi-line text using plt.text with custom line spacing?

Given the goal to display multi-line text with extra space between lines, which code snippet achieves this?

A

plt.text(0.5, 0.5, 'Line 1\nLine 2\nLine 3', ha='center', va='center', lineheight=2)
plt.show()

B

plt.text(0.5, 0.5, 'Line 1\nLine 2\nLine 3', ha='center', va='center', line_spacing=2)
plt.show()

C

plt.text(0.5, 0.5, 'Line 1\nLine 2\nLine 3', ha='center', va='center', spacing=2)
plt.show()

D

plt.text(0.5, 0.5, 'Line 1\nLine 2\nLine 3', ha='center', va='center', linespacing=2)
plt.show()

💡 Hint

Check the exact parameter name for line spacing in plt.text.

The correct parameter to control line spacing in matplotlib text is linespacing. Other options are invalid and cause errors.

🧠 Conceptual

advanced

How does matplotlib handle multi-line text alignment?

When using multi-line text in matplotlib, how does the ha (horizontal alignment) parameter affect the text?

A <p><code>ha</code> aligns the entire block of multi-line text as a single unit relative to the x coordinate.</p>

B <p><code>ha</code> aligns each line of the multi-line text relative to the specified x coordinate.</p>

C <p><code>ha</code> only affects the first line of the multi-line text.</p>

D <p><code>ha</code> has no effect on multi-line text alignment.</p>

💡 Hint

Think about how each line is positioned horizontally.

The ha parameter aligns each line individually relative to the x coordinate, so all lines share the same horizontal alignment.

❓ data_output

expert

What is the bounding box size of this multi-line text?

Given this code, what is the approximate bounding box width and height of the multi-line text in display units?

Matplotlib

import matplotlib.pyplot as plt

fig, ax = plt.subplots()
text_obj = ax.text(0.5, 0.5, 'Hello\nWorld', ha='center', va='center', fontsize=12)
fig.canvas.draw()
bbox = text_obj.get_window_extent()
width, height = bbox.width, bbox.height
print(round(width), round(height))

A "The width and height are both about 45"

B "The width is about 30 and the height is about 60"

C "The width is about 60 and the height is about 30"

D "The width and height are both about 15"

💡 Hint

Remember that width is usually larger than height for horizontal text, and multi-line text height increases with lines.

The bounding box width is roughly the width of the longest line in pixels (~60), and height is roughly the height of two lines (~30) at fontsize 12.

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