Question 1

Question 4Assertion (A): A histogram is basically used to represent data provided in the form of groups spread in non-continuous ranges.Reasoning (R): matplotlib.pyplot.hist() function is used to compute and create histogram of a variable.Both A and R are true and R is the correct explanation of A.Both A and R are true but R is not the correct explanation of A.A is true but R is false.A is false but R is true.

Accepted Answer

A is false but R is true.ExplanationA histogram is used to represent data provided in the form of discrete or continuous ranges. The matplotlib.pyplot.hist() function is used to compute and create a histogram of a variable.

Question 2

Question 1Hindustan Departmental Stores sell items of daily use such as shampoo, soap and much more. They record the entire sale and purchase of goods month-wise so as to get a proper analysis of profit or loss in their business transactions.Following is the csv file containing the "Company Sales Data".Read the total profit of all months and show it using a line plot. Total profit data has been provided for each month. Generated line plot must include the following properties:X label name = Month NumberY label name = Total profit

Accepted Answer

import pandas as pd
import matplotlib.pyplot as plt
df = pd.read_csv("C:\company_sales_data.csv")
profitList = df['total_profit'].tolist()
monthList = df['month_number'].tolist()
plt.plot(monthList, profitList, label = 'Month-wise Profit data of last year')
plt.xlabel('Month number')
plt.ylabel("Profit in dollars")
plt.xticks(monthList)
plt.title('Company profit per month')
plt.yticks([100000, 200000, 300000, 400000, 500000])
plt.show()Output

Question 3

Question 2Anirudh is trying to write a code to plot line graph shown in the figure below. Help him fill in the blanks in the code and get the desired output.import matplotlib.pyplot as plt             # statement 1
x = [1, 2, 3]                               # statement 2
y = [2, 4, 1]                               # Statement 3
plt.plot(x, y, color = 'g')                 # statement 4
...............                             # statement 5
...............                             # statement 6
# giving a title to graph
plt. ............... ('My first graph!')    # statement 7
# Function to show the plot 
...............                             # statement 8
(i) Which of the above statements is responsible for plotting the values on canvas?Statement 8Statement 4Statement 1None of these(ii) Statements 5 & 6 are used to give names to X-axis and Y-axis as shown in Fig.1. Which of the following can fill those two gaps?1.plt.xlabel('X - axis') 
plt.ylabel('Y - axis')
2.plt.xtitle('x - axis')
plt.ytitle('y - axis')
3.plt.xlable('x - axis')
pit.ylable('x - axis') 
4.plt.xlabel('x axis')
plt.ylabel('y axis')
(iii) Raman has executed code with first 7 statements but no output is displayed. Which of the following statements will display the graph?plt.display()plt.show()matplotlib.pyplot.display()Both (b) & (c)(iv) The number of markers in the above line chart are:ZeroThreeInfiniteNot defined(v) Which of the following methods will result in displaying 'My first graph!' in the above graph?legend()label()title()Both (a) & (c)

Accepted Answer

(i) Statement 4Reason — The plt.plot() statement is used to plot y versus x data on the canvas in Matplotlib.(ii)plt.xlabel('X - axis') 
plt.ylabel('Y - axis')
Reason — The xlabel() and ylabel() functions are used to give labels to x-axis and y-axis respectively.(iii) plt.show()Reason — The plt.show() statement is used to display the graph.(iv) ThreeReason — There are three markers in the line chart, corresponding to the three data points (1, 2), (2, 4), and (3, 1).(v) title()Reason — The plt.title() method is used to set the title of the graph, which in this case is "My first graph!".

Question 4

Question 5Which of the following commands is used to install Matplotlib for coding?import plt.matplotlib as plotimport plot.matplotlib as ptimport matplotlib.plt as plotimport matplotlib.pyplot as plt

Accepted Answer

import matplotlib.pyplot as pltReason — The correct command to import Matplotlib for coding is import matplotlib.pyplot as plt. This is the standard way to import Matplotlib, where matplotlib.pyplot is the module that provides the plotting functions, and as plt assigns the alias plt to the pyplot module.

Question 5

Question 6Differentiate between figure and axes.

Accepted Answer

FigureAxesFigure is the outermost area of Matplotlib graph.Axes is the individual plot within the figure.It contains one or more than one axes.It contains two or three axis objects.It contains plots, legend, axis label, ticks, title etc.It contains title, an x-label and a y-label.It provides a canvas for the plot.It displays the data in a specific format.

Question 6

Question 7What is the use of subplot() function? Write its parameters.

Accepted Answer

The subplot() function is used to display multiple charts in the same window.The syntax of the subplot() function is: subplot(nrows, ncols, index).The parameters are:nrows: The number of rows in the grid of subplots.ncols: The number of columns in the grid of subplots.index: The index of the subplot to create, starting from 1 and increasing from left to right, top to bottom.

Question 7

Question 8Write a Python program to draw a line with a suitable label in the X-axis and Y-axis, and a title.

Accepted Answer

import matplotlib.pyplot as plt
plt.plot([1, 2, 3, 4, 5], [2, 4, 6, 8, 10])
plt.title("Line Graph")
plt.xlabel("X-axis")
plt.ylabel("Y-axis")
plt.show()Output

Question 8

Question 9Write a Python program to plot two or more lines with legends, different widths and colors.

Accepted Answer

import matplotlib.pyplot as plt
x1 = [10,20,30]
y1 = [20,40,10]
plt.plot(x1, y1, color='blue', linewidth=3, label='line1')
x2 = [10,20,30]
y2 = [40,10,30]
plt.plot(x2, y2, color='red', linewidth=4, label='line2')
plt.legend()
plt.show()Output

Question 9

Question 10Write a Python program to plot two or more lines and set the line markers.

Accepted Answer

import matplotlib.pyplot as plt
x1 = [10,20,30]
y1 = [20,40,10]
plt.plot(x1, y1, marker='o', label='line1-circle')
x2 = [10,20,30]
y2 = [40,10,30]
plt.plot(x2, y2, marker='s', label='line2-square')
plt.show()Output

Question 10

Question 11Write a Python program to display a bar chart of the number of students in a class. Use different colors for each bar.Sample data:Class: I, II, III, IV, V, VI, VII, VIII, IX, XStrengths: 40, 43, 45, 47, 49, 38, 50, 37, 43, 39

Accepted Answer

import matplotlib.pyplot as plt
classes = ['I', 'II', 'III', 'IV', 'V', 'VI', 'VII', 'VIII', 'IX', 'X']
strengths = [40, 43, 45, 47, 49, 38, 50, 37, 43, 39]
plt.bar(classes, strengths, color=['red', 'green', 'blue', 'yellow', 'orange', 'purple', 'pink', 'brown', 'gray', 'black'])
plt.title('Number of Students in Each Class')
plt.xlabel('Class')
plt.ylabel('Number of Students')
plt.show()Output

Question 11

Question 12Write a Python program to display a horizontal bar chart of the number of students in a class.Sample data:Class: I, II, III, IV, V, VI, VII, VIII, IX, XStrengths: 40, 43, 45, 47, 49, 38, 50, 37, 43, 39

Accepted Answer

import matplotlib.pyplot as plt
classes = ['I', 'II', 'III', 'IV', 'V', 'VI', 'VII', 'VIII', 'IX', 'X']
strengths = [40, 43, 45, 47, 49, 38, 50, 37, 43, 39]
plt.barh(classes, strengths)
plt.title('Number of Students in Each Class')
plt.xlabel('Number of Students')
plt.ylabel('Class')
plt.show()Output

Question 12

Question 13Plot a line graph for: y2 = 4*x

Accepted Answer

import matplotlib.pyplot as plt
import numpy as np
x = np.arange(1, 5)
y = np.sqrt(4 * x)
plt.plot(x, y)
plt.title('Line Graph of y² = 4x')
plt.xlabel('x')
plt.ylabel('y')
plt.show()Output

Question 13

Question 14Write a Python program to plot the function y = x2 using the Matplotlib library.

Accepted Answer

import matplotlib.pyplot as plt
import numpy as np

x = np.arange(1, 5)
y = x ** 2
plt.plot(x, y)

plt.title('Line Graph of y = x²')
plt.xlabel('x')
plt.ylabel('y')

plt.show()Output

Question 14

Question 15Name the various methods used with pyplot object.

Accepted Answer

The various methods used with 'pyplot' object are as follows:Plotting methods — plot(), scatter(), bar(), hist() and pie().Labeling and titling methods — xlabel(), ylabel() and title().Legend methods — legend().axis methods — axis(), xlim(), ylim(), xticks() and yticks().grid methods — grid().figure and axes methods — figure(), subplots().display and save methods — show(), savefig() and close().

Question 15

Question 16Write the specific purpose of the following functions used in plotting:(a) show()(b) legend()

Accepted Answer

(a) show() — The purpose of the show() function is to display the plot.(b) legend() — The purpose of the legend() function is to add a legend to the plot. In a chart/graph, there may be multiple datasets plotted. To distinguish among various datasets plotted in the same chart, legends are used. Legends can be different colors/patterns assigned to different specific datasets. The legends are shown in a corner of a chart/graph.

Question 16

Question 17Plot a histogram of a class test of 40 students based on random sets of marks obtained by the students (MM=100).

Accepted Answer

import matplotlib.pyplot as plt
import numpy as np
marks = np.random.randint(0, 101, 40)
plt.hist(marks)
plt.title('Class Test Marks')
plt.xlabel('Marks')
plt.ylabel('Frequency')
plt.show()Output

Question 17

Question 18A list, namely temp contains average temperature for seven days of last week. You want to see how the temperature changes in the last seven days. Which chart type will you plot for the same and why?

Accepted Answer

A line chart is the suitable choice for visualizing how the temperature changed over the last seven days. The line chart shows trends over time and displays continuous data, making it ideal for representing temperature values. The chart's ability to connect data points allows viewers to easily observe temperature trends and understand variations across the seven-day period.

Question 18

Question 19Collect data about colleges in Delhi University or any other university of your choice and number of courses they run for Science, Commerce and Humanities, store it in a CSV file and present it using a bar plot.

Accepted Answer

import pandas as pd
import matplotlib.pyplot as plt

data = {"Stream": ["Science", "Commerce", "Humanities"], 
        "Number of Courses": [12, 10, 15] 
}

df = pd.DataFrame(data)
df.to_csv('du_colleges.csv', index=False)

df = pd.read_csv("du_colleges.csv")
plt.bar(df["Stream"], df["Number of Courses"])
plt.xlabel("Stream")
plt.ylabel("Number of Courses")
plt.title("Number of Courses in Each Stream")
plt.show()Output

Question 19

Question 20What is a histogram? How do you create histograms in Python?

Accepted Answer

A histogram is a summarization tool for discrete or continuous data, providing a visual interpretation of numerical data by showing the number of data points that fall within a specified range of values.The hist() function of the Pyplot module is used to create and plot a histogram from a given sequence of numbers. The syntax for using the hist() function in Pyplot is as follows:matplotlib.pyplot.hist(x, bins = None, cumulative = False, histtype = 'bar', align = 'mid', orientation = 'vertical', ).

Question 20

Question 21What are the various types of histograms that can be created through hist() function?

Accepted Answer

The hist() function in Matplotlib's Pyplot module allows creating various types of histograms. These include the default bar histogram (histtype='bar'), step histogram (histtype='step'), stepfilled histogram (histtype='stepfilled'), barstacked histogram (histtype='barstacked').

Data Visualization using Matplotlib

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