Text boxes with bbox in Matplotlib - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of text box with bbox style

What will be the color of the text box border in the following matplotlib code?

Matplotlib

import matplotlib.pyplot as plt
fig, ax = plt.subplots()
ax.text(0.5, 0.5, 'Hello', bbox=dict(facecolor='yellow', edgecolor='red', boxstyle='round'))
plt.show()

A The border color is red

B The border color is yellow

C The border color is black

D There is no border color

💡 Hint

Check the 'edgecolor' parameter inside bbox dictionary.

The 'edgecolor' parameter sets the border color of the text box. Here it is set to 'red'.

❓ data_output

intermediate

Number of text boxes created

How many text boxes with bounding boxes will be displayed by this code?

Matplotlib

import matplotlib.pyplot as plt
fig, ax = plt.subplots()
for i in range(3):
    ax.text(i, i, f'Text {i}', bbox=dict(facecolor='blue', alpha=0.3))
plt.show()

A 4

B 1

C 3

D 0

💡 Hint

Count how many times ax.text is called inside the loop.

The loop runs 3 times, each time creating one text box with bbox.

🔧 Debug

advanced

Identify the error in bbox usage

What error will this code raise when run?

Matplotlib

import matplotlib.pyplot as plt
fig, ax = plt.subplots()
ax.text(0.5, 0.5, 'Error test', bbox=dict(facecolor='green', edgecolor='blue', boxstyle='circle'))
plt.show()

A SyntaxError: invalid syntax

B No error, plot shows correctly

C TypeError: bbox must be a dict

D ValueError: Unknown boxstyle 'circle'

💡 Hint

Check if 'circle' is a valid boxstyle in matplotlib.

'circle' is not a valid boxstyle name in matplotlib, causing a ValueError.

❓ visualization

advanced

Effect of alpha in bbox facecolor

Which option best describes the visual effect of alpha=0.5 in the bbox facecolor?

Matplotlib

import matplotlib.pyplot as plt
fig, ax = plt.subplots()
ax.text(0.5, 0.5, 'Alpha test', bbox=dict(facecolor='red', alpha=0.5))
plt.show()

A The text box background is fully transparent

B The text box background is semi-transparent red

C The text box background is fully opaque red

D The text box background is blue

💡 Hint

Alpha controls transparency from 0 (transparent) to 1 (opaque).

Alpha=0.5 means the red background is half transparent, so you see some background behind it.

🧠 Conceptual

expert

Understanding bbox boxstyle options

Which of these is NOT a valid boxstyle option for bbox in matplotlib text boxes?

A diamond

B square

C round

D larrow

💡 Hint

Check matplotlib documentation for valid boxstyle names.

'diamond' is not a recognized boxstyle in matplotlib, unlike 'round', 'square', and 'larrow'.