KTU Python for machine learning Sample Question Paper and Answer Key Dec 2020

 

APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY THIRD SEMESTER B.TECH DEGREE EXAMINATION, DECEMBER 2020
Course Code: CST283
Course Name: Python for Machine Learning
Max. Marks: 100				Duration: 3 Hours
PART A
		Answer all questions. Each question carries 3 marks			Marks
	1	Explain the input statement with an example. How the type conversion is done			3
	2	Illustrate the concept of modules and explain with example how they are used in Python programs			3
	3	Write a Python program to print all prime numbers less than 100.			3
	4	Demonstrate Lambda function with an example			3
	5	Use list to read n names and print the names in alphabetical order			3
	6	Let D ={‘a’:10,’b’:20} be a dictionary. Write commands to a)      Add a new key value pair(‘c’:30) b)      Update the value correspond to the key ‘a’ to 100 c)      Remove the entry corresponds to the key ‘b’			3
	7	Write a Python class named ‘Circle’ with attribute radius and two methods which will compute the area and the perimeter of a given circle.			3
	8	Describe the exception handling mechanism in Python with an example			3
	9	Illustrate numpy arrays with example. How indexing,slicing and sorting is done with examples.			3
	10	Write Python code to plot a sin wave (from 0 to 2*pi) using matplotlib library with proper title, xlabel and ylabel.			3
PART B
Answer any one full question from each module. Each question carries 14 marks
		Module 1
	11	a)      Describe the waterfall model of software development process with a neat figure. b)      Write a Python script to find the number of digits in the factorial of a given number.(Use python built-in modules functions)			9     5
	12	a)      Write a program to find the Area of a circle given its circumference b)      List the different types of operators in Python			7   7
		Module 2
	13	a) Generate the Fibonacci series upto n.( 0 1 1 2 3 5....n) b) Explain with an example ,the use of functions and how functions are defined and called in Python.			7   7
	14	a) Given three points (x1,y1 ) ,(x2,y2) and (x3,y3), check whether they form a triangle using a python script. b) Explain recursion with an example and mention the advantages and disadvantages of recursion			7     7
		Module 3
	15	a)Write a program to find the median of list of numbers using lists b)Explain any four set operations in python with examples			6   8
	16	a) Write a Python code to create a function called frequency that takes a string and prints the letters in non-increasing order of the frequency of their occurrences. Use dictionaries. b) Distinguish between Tuple and Lists			8       6
		Module 4
	17	a)Illustrate Polymorphism and Operator overloading. b) Implement a Complex class to read and display complex numbers with real and imaginary parts are attributes. Overload + operator to add two complex numbers.			4     10
	18	Explain inheritance and different forms of inheritance .How they are implemented in Python.			14
		Module 5
	19	a)Explain any 3 methods of os and sys module. b)Write a Python program to create a text file. Read the contents of the file, encrypt every character in the file with a distance of 3 and write it to a new file. Eg:yak is encrypted as bdn.			6   8
	20	a) Discuss about data analysis and visualization in Python b)There exist a CSV file stud.csv with following columns( rno,name,place,mark) of n students. Write commands to do the following using pandas library. a)      Read and display the content of stud.csv file b)      Display the top 10 rows c)      Display the students list in the order of name d)     Display the students list in the descending order of marks e)      Display the maximum mark and average mark f)       Plot the histogram of mark g)      Remove the column titled place.			7   7

 

Answer Key

APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY THIRD SEMESTER B.TECH DEGREE EXAMINATION, DECEMBER 2020
Course Code: CST283
Course Name: Python for Machine Learning
Max. Marks: 100				Duration: 3 Hours
PART A
		Answer all questions. Each question carries 3 marks			Marks
	1	S=input(‘enter a name’) .....using input statement N=int(input(‘enter a number’)).....type conversion			1.5 1.5
	2	explanation of module concept- valid three points use of module with examples-   A module is a file containing Python definitions and statements. Python modules have a filename and end with the extension .py. We use modules to break down large programs into small manageable and organized files. Furthermore, modules provide re usability of code. We can define our most used functions in a module and import it, instead of copying their definitions into different programs. We can use the module in the following ways: >>>import math  >>>math.sqrt(25) Import with renaming >>>import math as m  >>m.sqrt(25) We can import specific names from a module without importing the module as a whole. Here is an example. # import only pi from math module  from math import pi  We can import all names(definitions) from a module using the following construct:  >>>from math import *  # import all names from the standard module math			1.5 1.5
	3	Program logic Syntax and correctness			1.5 1.5
	4	Demonstration of Lambda function Example     In Python, an anonymous function is a function that is defined without a name. These functions are called anonymous because they are not declared in the standard manner by using the def keyword. You can use the lambda keyword to create small anonymous functions.   Syntax of Lambda Function in python lambda [arg1 [,arg2,.....argn]]:expression Lambda functions can have any number of arguments but only one expression. The expression is evaluated and returned. Lambda functions can be used wherever function objects are required. Example of Lambda Function in python Here is an example of lambda function that doubles the input value. # Program to show the use of lambda functions  double = lambda x: x * 2 print(double(5))			2 1
	5	Program logic Syntax correctness n=int(input("Enter the number of names....")) names=[] print("Enter {} names".format(n)) for i in range(n):     nam=input()     names.append(nam) names.sort() print("names in alphabetical order") for nam in names:     print(nam)			1.5 1.5
	6	D[‘c’]=30 D[‘a’]=200 D.pop(‘b’)			1 1 1
	7	Class definition Member function definition			1 2
	8	Definition Handling exception Example   What is Exception? An exception is an event, which occurs during the execution of a program that disrupts the normal flow of the program's instructions. In general, when a Python script encounters a situation that it cannot cope with, it raises an exception. An exception is a Python object that represents an error. When a Python script raises an exception, it must either handle the exception immediately otherwise it terminates and quits. Handling an exception If you have some suspicious code that may raise an exception, you can defend your program by placing the suspicious code in a try: block. After the try: block, include an except: statement, followed by a block of code which handles the problem as elegantly as possible. Syntax Here is simple syntax of try....except...else blocks  try:    You do your operations here;    ...................... except ExceptionI:    If there is ExceptionI, then execute this block. except ExceptionII:    If there is ExceptionII, then execute this block.    ...................... else:    If there is no exception then execute this block. For example, we might prompt the user for the name of a file and then try to open it. If the file doesn’t exist, we don’t want the program to crash; we want to handle the exception: filename =input('Enter a file name: ') try:     f = open (filename, "r") except IOError:     print ('There is no file named', filename) else:     f.close()   As previously mentioned, the portion that can cause an exception is placed inside the try block.			1 1 1
	9	Creating numpy arrays Indexing/slicing Sorting   import numpy as np  A = np.array([[1, 2, 3], [3, 4, 5]])  Indexing/slicing A=np.array([[1,2,3],[4,5,6],[7,8,9]]) print(A[2]) [7 8 9] print(A[2,2]) 9 print(A[2][2]) 9 print(A[1:,1:]) [[5 6]       [8 9]]   print(A[:2,1:]) [[2 3]      [5 6]] A.sort() will sort the array elements			1 1 1
	10	from matplotlib import pyplot as plt import numpy as np  import math #needed for definition of pi  x = np.arange(0, math.pi*2, 0.05) y = np.sin(x)  plt.plot(x,y)  plt.xlabel("angle")  plt.ylabel("sine")  plt.title('sine wave')  plt.show()			3
PART B
Answer any one full question from each module. Each question carries 14 marks
		Module 1
	11	a)Explanation- Fig   There is much more to programming than writing lines of code.Computer Engineers refer to the process of planning and organizing a program as Software Development. There are several approaches to software development.One version is known as the waterfall model. The waterfall model consists of several phases: 1.Customer request:In this phase, the programmer receives a broad statement a problem to be solved. This is the user requirement specification phase. 2.Analysis: Determines what the program will do. This is viewed as the process of clarifying the specification for the problem. 3.Design: Determines how the program will do the task 4.Implementation: The programmers write the program. This step is also called coding phase. 5.Integration: Large programs have many parts. In the integration phase, these parts are brought together into a smoothly functioning system as a whole. 6. Maintenance: Programs usually have a long life, a span of 5-15 years is common. During this time, requirements change, errors are detected and minor or major modifications are made.   b) import math n=int(input('enter a number')) f=math.factorial(n) print("factorial=",f) print("number of digits",len(str(f)))			6+2    1                                         5
	12	a)      Circumference= 2*pi*r compute r from this  area=2*pi*r b)      Arithmetic Operators Comparison (Relational) Operators Assignment Operators Logical Operators Bitwise Operators Membership Operators Identity Operators			7         7
		Module 2
	13	a)logic   syntax and correctness hint: sort the list and get the middle value b)Functions and use  Function definition/calling example The following are the two simple reasons to write a function Creating a new function gives you an opportunity to name a group of statements. Functions can simplify  a program by hiding a complex computation behind a single command. Creating a new function can make a program smaller by eliminating repetitive code. Syntax of Function def function_name(parameters):   """docstring"""       statement(s)      [ return value(s)/expression]			4 3   4 3
	14	a)logic syntax and correctness   b)definition example advantages and disadvantages   Recursion is a method of solving problems that involves breaking a problem down into smaller and smaller sub problems until you get to a small enough 4problem so that it can be solved trivially. Usually recursion involves a function calling itself. While it may not seem like much on the surface, recursion allows us to write elegant solutions to problems that may otherwise be very difficult to program. Advantages of recursion Recursive functions make the code look clean and elegant. A complex task can be broken down into simpler sub-problems using recursion. Sequence generation is easier with recursion than using some nested iteration. Disadvantages of recursion Sometimes the logic behind recursion is hard to follow through. Recursive calls are expensive (inefficient) as they take up a lot of memory and time. Recursive functions are hard to debug.			4 3     1 2 4
		Module 3
	15	a)      logic syntax and correctness b)  >>> A={3,2,1,4} >>> A.add(5) >>> A {1, 2, 3, 4, 5} >>> B=A.copy() >>> B {1, 2, 3, 4, 5} >>> B.clear() >>> B set() >>> A {1, 2, 3, 4, 5} >>> A.discard(5) >>> A {1, 2, 3, 4} >>> A.update({5,6}) >>> A {1, 2, 3, 4, 5, 6} >>> B={1,2} >>> B.issubset(A) True >>> A.union(B) {1, 2, 3, 4, 5, 6} >>> A.intersection(B) {1, 2} >>> A.difference(B) {3, 4, 5, 6}			3 3   4*2
	16	a)      logic, syntax, correctness def list_of_frequency(s):     d=dict()     for c in s:         d[c]=d.get(c,0)+1     print("letter count in the decresing order")     l=list(d.items())     l.sort(key=lambda x:x[1],reverse=True)     print(l)   s=input("Enter the string…..") list_of_frequency(s) b)      any valid 3 points Definition difference Mutability indexing			4+2+2                         6
		Module 4
	17	a)definition of polymorphism and operator overloading b)class defn member function to read member function to display overloaded + operator ( _add_  function)			2+2   2 2 2 4
	18	Illustration of inheritance Different types Sample Python code showing different types of inheritance			3 3   8
		Module 5
	19	a)3 os functions 3 sys function b)opening file reading file encryption writing file closing file			3 3   1 1 4 1 1
	20	a)      Illustration of plotting library matplotlib Illustration of numpy and pandas   b)import pandas as pd df = pd.read_csv("stud.csv") print(df) print(df.head(10)) print(df.sort_values(by='name')) print(df.sort_values(by='mark',ascending=False)) print(df['mark'].max(),df['mark'].mean()) import matplotlib.pyplot as plt plt.hist(df['mark']) df.drop(['place'],axis=1,inplace=True) print(df)			3 4           7*1=7