Pyplot interface overview in Matplotlib - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this Pyplot code?

Look at this code that uses matplotlib.pyplot. What will it show?

Matplotlib

import matplotlib.pyplot as plt
plt.plot([1, 2, 3], [4, 5, 6])
plt.title('Simple Line')
plt.xlabel('X axis')
plt.ylabel('Y axis')
plt.show()

A A line graph with points (1,4), (2,5), (3,6) and labeled axes

B A scatter plot with points (1,4), (2,5), (3,6) but no lines

C A bar chart with bars at 1, 2, 3 with heights 4, 5, 6

D An empty plot with only axis labels

💡 Hint

Remember, plt.plot() draws lines connecting points.

The plt.plot() function draws a line graph connecting the points given by the x and y lists. The labels and title appear as expected.

❓ data_output

intermediate

How many lines are drawn by this Pyplot code?

Count the number of lines that will appear after running this code.

Matplotlib

import matplotlib.pyplot as plt
plt.plot([1, 2, 3], [4, 5, 6])
plt.plot([1, 2, 3], [6, 5, 4])
plt.show()

A 2

B 3

C 1

D 0

💡 Hint

Each plt.plot() call adds one line.

There are two plt.plot() calls, so two lines will be drawn on the same plot.

❓ visualization

advanced

What does this Pyplot code visualize?

Examine the code below. What kind of plot will it produce?

Matplotlib

import matplotlib.pyplot as plt
import numpy as np
x = np.linspace(0, 2 * np.pi, 100)
y = np.sin(x)
plt.plot(x, y)
plt.fill_between(x, y, color='skyblue', alpha=0.5)
plt.title('Sine Wave with Fill')
plt.show()

A A scatter plot of sine values with blue dots

B A sine wave line plot with the area under the curve shaded in blue

C A bar chart showing sine values at discrete points

D A line plot of cosine wave with shaded area

💡 Hint

fill_between colors the area under the curve.

The code plots a sine wave line and shades the area under it with a semi-transparent blue color.

🔧 Debug

advanced

What error does this Pyplot code raise?

Look at this code snippet. What error will it cause when run?

Matplotlib

import matplotlib.pyplot as plt
plt.plot([1, 2, 3], [4, 5])
plt.show()

A SyntaxError: invalid syntax

B TypeError: unsupported operand type(s)

C ValueError: x and y must have same first dimension

D No error, plot will display

💡 Hint

Check if the x and y lists have the same length.

The x list has 3 elements but y has only 2, so plt.plot() raises a ValueError about dimension mismatch.

🚀 Application

expert

Which option produces a plot with two subplots side by side?

You want to create two plots side by side using Pyplot. Which code will do this correctly?

A

import matplotlib.pyplot as plt
plt.subplots(2, 1)
plt.plot([1, 2, 3], [4, 5, 6])
plt.plot([1, 2, 3], [6, 5, 4])
plt.show()

B

import matplotlib.pyplot as plt
plt.subplot(2, 1)
plt.plot([1, 2, 3], [4, 5, 6])
plt.subplot(2, 2)
plt.plot([1, 2, 3], [6, 5, 4])
plt.show()

C

import matplotlib.pyplot as plt
fig, axs = plt.subplots(2)
axs[0].plot([1, 2, 3], [4, 5, 6])
axs[1].plot([1, 2, 3], [6, 5, 4])
plt.show()

D

import matplotlib.pyplot as plt
fig, axs = plt.subplots(1, 2)
axs[0].plot([1, 2, 3], [4, 5, 6])
axs[1].plot([1, 2, 3], [6, 5, 4])
plt.show()

💡 Hint

Use plt.subplots(rows, columns) to create a grid of plots.

Option D correctly creates a figure with 1 row and 2 columns of subplots, then plots on each axis separately.