Chapter-16
Question 1.
Which is a python package used for 2D graphics?
a) matplotlib.pyplot
b) matplotlib.pip
c) matplotlib.numpy
d) matplotlib.plt
Answer:
a) matplotlib.pyplot
Question 2.
Identify the package manager for Python packages, or modules.
a) Matplotlib
b) PIP
c) plt.show()
d) python package
Answer:
b) PIP
Question 3.
Read the following code: Identify the purpose of this code and choose the right option from the following.
C:\Users\YourName\AppData\Local\Programs\Python\Python36-32\Scripts > pip – version
a) Check if PIP is Installed
b) Install PIP
c) Download a Package
d) Check PIP version
Answer:
d) Check PIP version
Question 4.
Read the following code: Identify the purpose of this code and choose the right option from the following.
C:\Users\Your Name\AppData\Local\Programs\Python\Python36-32\Scripts > pip list
a) List installed packages
b) list command
c) Install PIP
d) packages installed
Answer:
a) List installed packages
Question 5.
To install matplotlib, the following function will be typed in your command prompt. What does “-U” presents?
Python -m pip install -U pip
a) downloading pip to the latest version
b) upgrading pip to the latest version
c) removing pip
d) upgrading matplotlib to the latest version
Answer:
b) upgrading pip to the latest version
Question 6.
Observe the output figure. Identify the coding for obtaining this output.
a) import matplotlib.pyplot as plt
plt.plot([1,2,3],[4,5,1])
plt.show()
b) import matplotlib.pyplot as plt
plt.plot([1,2],[4,5])
plt.show()
c) import matplotlib.pyplot as plt
plt.plot([2,3],[5,1])
plt.show()
d) import matplotlib.pyplot as plt
plt .plot ([1,3], [4,1 ])
plt.show()
Answer:
a) import matplotlib.pyplot as plt
plt.plot([1,2,3],[4,5,1])
plt.show()
Question 7.
Read the code:
a. import matplotlib.pyplot as pit
b. plt.plot(3,2)
c. plt.show()
Identify the output for the above coding
Answer:
Question 8.
Which key is used to run the module?
a) F6
b) F4
c) F3
d) F5
Answer:
d) F5
Question 9.
Identify the right type of chart using the following hints.
Hint 1: This chart is often used to visualize a trend in data over intervals of time.
Hint 2: The line in this type of chart is often drawn chronologically.
a) Line chart
b) Bar chart
c) Pie chart
d) Scatter plot
Answer:
a) Line chart
Question 10.
Read the statements given below. Identify the right option from the following for pie chart. Statement A : To make a pie chart with Matplotlib, we can use the plt.pie() function.
Statement B : The autopct parameter allows us to display the percentage value using the Python string formatting.
a) Statement A is correct
b) Statement B is correct
c) Both the statements are correct
d) Both the statements are wrong
Answer:
b) Statement B is correct
II Answer the following questions (2 marks)
Question 1
Define: Data Visualization.
Answer:
- Data Visualization is the graphical representation of information and data.
- The objective of Data Visualization is to communicate information visually to users.
- Data visualization uses statistical graphics.
Question 2.
List the general types of data visualization.
Answer:
- Charts
- Tables
- Graphs
- Maps
- Infographics
- Dashboards
Question 3.
List the types of Visualizations in Matplotlib.
Answer:
There are many types of Visualizations under Matplotlib. Some of them are: Line plot
- Scatter plot
- Line plot
- Histogram
- Box plot
- Bar chart and
- Pie chart
Question 4.
How will you install Matplotlib?
Answer:
- Matplotlib can be installed using pip software.
- Pip is a management software for installing python packages.
- Importing Matplotlib using the command: import matplotlib.pyplot as plt
- Matplotlib can be imported in the workspace.
Question 5.
Write the difference between the following functions: plt. plot([1,2,3,4]), plt. plot ([1,2,3,4],
[14, 9,16]).
Answer:
|
plt.plot([1,2,3,4])
|
plt.plot([1,2,3,4], [1,4,9,16]) |
|---|---|
| It refers y value as [1,2,3,4] | It refers x and y values as ([1,2,3,4], [1,4,9,16]) |
| Indirectly it refers x values as [0,1,2,3] (0,1) (1,1) (2,3) (3,4) |
Directly x and y values are given as (1,1) (2,4) (3,9) (4,16) |
III. Answer the following questions (3 marks)
Question 1.
Draw the output for the following data visualization plot.
import matplotlib.pyplot as plt
plt.bar([1,3,5,7,9],[5,2,7,8,2], label=”Example one”)
plt.bar([2,4,6,8,10],[8,6,2,5,6], label=:”Example two”, color=’g’)
plt.legend()
plt.xlabel(‘bar number’)
plt.ylabel(‘bar height’)
plt.title(‘Epic Graph\nAnother Line! Whoa’)
plt.show()
Output:
Question 2.
Write any three uses of data visualization.
Answer:
- Data Visualization help users to analyze and interpret the data easily.
- It makes complex data understandable and usable.
- Various Charts in Data Visualization helps to show relationship in the data for one or more variables
Question 3.
Write the coding for the following:
a) To check if PIP is Installed in your PC.
b) To Check the version of PIP installed in your PC.
c) To list the packages in matplotlib.
Answer:
a) To check if PIP is Installed in your PC.
- Incommand prompt type pip – version.
- If it is installed already, you will get version.
- Command : Python – m pip install – U pip
b) To Check the version of PIP installed in your PC.
C:\ Users\ YourName\ AppData\ Local\ Programs\ Py thon\ Py thon36-32\ Scripts>pip-version
c) To list the packages in matplotlib.
C:\ Users\ Y ou rName\ AppData\ Local\ Programs\ Py thon\ Py thon36-32\ Scripts>pip list
Question 4.
Write the plot for the following pie chart output.
Coding:
import matplotlib.pyplot as plt
slices = [7,2,2,13]
activities = [„sleeping‟, „eating‟, „working‟, „playing‟]
plt.pie(slices, labels=activities, atopct = „y.1.1 f%%‟)
plt.title(„Interesting Graph Ceck It Out‟)
plt.show()
Output:
IV. Answer the following questions (5 Marks)
Question 1.
Explain in detail the types of pyplots using Matplotlib.
Answer:
Matplotlib allows us to create different kinds of plots ranging from histograms and scatter plots to bar graphs and bar charts.
Line Chart:
- A Line Chart or Line Graph is a type of chart which displays information as a series of data points called ‘markers’ connected by straight line segments.
- A Line Chart is often used to visualize a trend in data over intervals of time – a time series – thus the line is often drawn chronologically.
Program for Line plot:
import matplotlib.pyplot as pit years = [2014, 2015, 2016, 2017, 2018] total_populations = [8939007, 8954518,, 8960387,8956741,8943721]
plt. plot (“years, total_populations)
plt. title (“Year vs Population in India”)
plt.xlabel (“Year”)
plt.ylabel (“Total Population”)
plt.showt
In this program,
Plt.titlet() →→7 specifies title to the graph
Plt.xlabelt) →→ specifies label for X-axis
Plt.ylabelO →→ specifies label for Y-axis
Output:
Bar Chart:
- A BarPlot (or Bar Chart) is one of. the most common type of plot. It shows the relationship between a numerical variable and a categorical variable.
- Bar chart represents categorical data with rectangular bars. Each bar has a height corresponds to the value it represents.
- The bars can be plotted vertically or horizontally.
- It is useful when we want to compare a given numeric value on different categories.
- To make a bar chart with Matplotlib, we can use the plt.bart) function.
Program:
import matplotlib.pyplot as pit
# Our data
labels = [“TAMIL”, “ENGLISH”, “MATHS”, “PHYSICS”, “CHEMISTRY”, “CS”]
usage = [79.8,67.3,77.8,68.4,70.2,88.5]
# Generating the y positions. Later, we’ll use them to replace them with labels. y_positions = range (len(labels))
# Creating our bar plot
plt.bar (y_positions, usage)
plt.xticks (y_positions, labels)
plt.ylabel (“RANGE”)
pit.title (“MARKS”)
plt.show()
Output:
Pie Chart:
- Pie Chart is probably one of the most common type of chart.
- It is a circular graphic which is divided into slices to illustrate numerical proportion.
- The point of a pie chart is to show the relationship of parts out of a whole.
- To make a Pie Chart with Matplotlib, we can use the plt.pie () function.
- The autopct parameter allows us to display the percentage value using the Python string formatting.
Program:
import matplotlib.pyplot as pit
sizes = [89, 80, 90,100, 75]
labels = [“Tamil”, “English”, “Maths”,
“Science”, “Social”]
plt.pie (sizes, labels = labels,
autopct = “%.2f”)
plt.axesfj.set aspect (“equal”)
plt.showt()
Output:
Question 2.
Explain the various buttons in a matplotlib window.
Answer:
Various buttons in a matplotlib window:
Home Button:
The Home Button will help one to begun navigating the chart. If you ever want to return back to the original view, you can click on this.
Forward/Back buttons:
Forward/Back buttons can be used like the Forward and Back buttons in browser. Click these to move back to the previous point you were at, or forward again.
Pan Axis:
This cross-looking button allows us to click it, and then click and drag graph around.
Zoom :
The Zoom button lets us click on it, then click and drag a square would like to zoom into specifically.
Zooming in will require a left click and drag. Zoom out with a right click and drag.
Configure Subplots:
Configure Subplots button allows us to configure various spacing options with figure and plot.
Save Figure :
Save Figure button will allow us to save figure in various forms.
Question 3.
Explain the purpose of the following functions:
Answer:
a) plt.xlabel:
plt.xlabel Specifies label for X -axis
b) plt.ylabel:
plt.ylabel is used to specify label for y-axis
c) plt.title :
plt.title is used to specify title to the graph or assigns the plot title.
d) plt.legend():
plt.legend() is used to invoke the default legend with plt
e) plt.show():
plhshowQ is used to display the plot.