Figure and axes creation in Data Analysis Python - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this figure and axes creation code?

Consider the following Python code using matplotlib to create a figure and axes. What will be the type of the variable ax?

Data Analysis Python

import matplotlib.pyplot as plt
fig, ax = plt.subplots()
print(type(ax))

A <class 'matplotlib.axes._subplots.AxesSubplot'>

B <class 'tuple'>

C <class 'list'>

D <class 'matplotlib.figure.Figure'>

💡 Hint

The plt.subplots() function returns a figure and axes object. The axes object is used to plot data.

The plt.subplots() function returns a tuple: the first element is a Figure object, and the second is an AxesSubplot object. The variable ax is the axes, so its type is matplotlib.axes._subplots.AxesSubplot.

❓ data_output

intermediate

How many axes are created in this figure?

What is the number of axes created by the following code?

Data Analysis Python

import matplotlib.pyplot as plt
fig, axs = plt.subplots(2, 3)
print(len(axs.flatten()))

A 5

B 3

C 6

D 2

💡 Hint

The plt.subplots(2, 3) creates a grid of 2 rows and 3 columns of axes.

The plt.subplots(2, 3) creates 2 rows and 3 columns of axes, so total axes are 2 * 3 = 6. The axs is a 2D array of axes, and flattening it gives a list of all 6 axes.

🔧 Debug

advanced

What error does this code raise?

Examine the code below. What error will it raise when run?

Data Analysis Python

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

A AttributeError: 'numpy.ndarray' object has no attribute 'plot'

B TypeError: 'int' object is not iterable

C ValueError: x and y must have same first dimension

D No error, plots successfully

💡 Hint

When plt.subplots(2) is called, ax is an array of axes, not a single axes.

Calling plt.subplots(2) creates a figure with 2 axes in a 1D array. The variable ax is an array, which does not have a plot method. Trying to call ax.plot() raises an AttributeError.

❓ visualization

advanced

Which option produces a figure with 4 subplots arranged in 2 rows and 2 columns?

Select the code snippet that creates a figure with 4 subplots arranged in 2 rows and 2 columns.

A fig, axs = plt.subplots(4, 1)

B fig, axs = plt.subplots(2, 2)

C fig, axs = plt.subplots(1, 4)

D fig, axs = plt.subplots(3, 2)

💡 Hint

The first argument is number of rows, the second is number of columns.

The plt.subplots(2, 2) creates 2 rows and 2 columns of subplots, totaling 4 subplots.

🧠 Conceptual

expert

What is the difference between fig.add_subplot() and plt.subplots()?

Choose the correct statement about the difference between fig.add_subplot() and plt.subplots() in matplotlib.

A <code>fig.add_subplot()</code> returns a figure object, while <code>plt.subplots()</code> returns only axes objects.

B <code>fig.add_subplot()</code> creates a new figure with multiple subplots, while <code>plt.subplots()</code> adds a subplot to an existing figure.

C <code>fig.add_subplot()</code> and <code>plt.subplots()</code> are identical and interchangeable.

D <code>fig.add_subplot()</code> adds a single subplot to an existing figure, while <code>plt.subplots()</code> creates a new figure and a grid of subplots.

💡 Hint

Think about whether a new figure is created or an existing figure is modified.

fig.add_subplot() is a method to add a single subplot to an existing figure object. plt.subplots() is a function that creates a new figure and a grid of subplots (axes). They serve different purposes.