subins2000/some-python-programs-ktu-cse.md

## some-python-programs-ktu-cse.md

      
    Raw
  

              some-python-programs-ktu-cse.md
            
          
    Python Programs


Copyleft Subin <subins2000 [at] gmail [dot] com>

Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0)


26/11/2017
https://gist.github.com/subins2000/fe2ac89c99fd4ee530d1c5848a114db1

August 2017


Write a program to calculate nCr with a functions for finding out factorial (2)


Answer
# Python3
def fact(n):
    if fact == 0:
        return 1
    # return will end the function call. So no need of elif here
    return n * fact(n - 1)

n = int(input('Enter value of n :'))
r = int(input('Enter value of r :'))

nCr = fact(n) / (fact(r) * fact(n - r))

print(nCr)


Write a program to generate all prime numbers in a given range (8)


Answer
# Python3
# Check if a gived number is prime or not. Returns a boolean
def isPrime(n):
    # Assume number is prime
    prime = True

    for i in range(2, n):
        if n % i == 0:
            # Our assumption is wrong. The number is divisible by a number other than 1 and the same number
            prime = False

            # No need to continue checking if it is found to be divisible once. So stop the loop
            break

    return prime

start = int(input('Enter start of range : '))
end = int(input('Enter end of range : '))

# end + 1 because we want to include the ending number too
for i in range(start, end + 1):
    if isPrime(i):
        print(i)


Write a Python program to find the roots of a quadratic equation. (4)


Answer
# Python3
import math

a = int(input('Enter value of a : '))
b = int(input('Enter value of b : '))
c = int(input('Enter value of c : '))

# Calculate discriminant = b^2 - 4*a*c
discriminant = math.sqrt(b ** 2 - (4 * a * c))

if discriminant < 0:
    print('Only imaginary solutions')
else:
    x1 = (-b + discriminant) / 2 * a
    x2 = (-b - discriminant) / 2 * a

    if discriminant == 0:
        print('Unique solution = ', x1)
    else:
        print('Solution 1 = ', x1)
        print('Solution 2 = ', x2)


Write a Python program to calculate the area of a circle, given the centre and a point on the perimeter. Use a function to find radius as the distance between two points. (5)


Answer
# Python3
import math

# Return coordinates of the point as a tuple where first value is x coordinate and the other, y coordinate
def getPoint():
    x = int(input('Enter x coordinate : '))
    y = int(input('Enter y coordinate : '))

    # Return a tuple
    return (x, y)

# Find the distance between two points
def findDistance(centre, point):
    # centre and point is a tuple.
    # centre[0] and point[0] will have x coordinate
    xDiff = centre[0] - point[0]
    yDiff = centre[1] - point[1]

    distance = math.sqrt((xDiff ** 2) + (yDiff ** 2))

    return distance

print('Enter coordinates of centre :')
centre = getPoint()

print('Enter coordinates of point on perimeter :')
point = getPoint()

radius = findDistance(centre, point)

area = math.pi * radius * radius

print('Area of circle : ', area)


Write a program to replace a substring with a new substring in the given string (7)


Answer
s = input('Enter a string : ')
find = input('Enter string to replace : ')
replace = input('Enter string to replace to : ')

findLength = len(find)
newS = ''

i = 0
while i < len(s):
    # The position from current until the end of 
    until = i + findLength
    
    # Check if characters from 'i'th position to 'until' is the substring we want to replace
    if s[i : until] == find:
        newS += replace

        i += findLength
    else:
        newS += s[i]
        i += 1

print(newS)


Write a program that reads a file and writes out a new file with the lines in reversed order. (7)


Answer
#Python3
file = open('file.txt', 'r')
out = open('out.txt', 'a')

# Get a list of each lines
contents = file.readlines()
# Reverse the list
reversedContents = reversed(contents)

for s in reversedContents:
    # Append each line to the output file
    out.write(s)

file.close()
out.close()


January 2017


Write a python program to find the sum of all odd terms in a group of n numbers entered by the user (3)


Answer
# Python3
s = 0

print('Enter the numbers. Type "done" when finished entering numbers.')
while True:
    number = input('Enter number : ')

    if number == 'done'
        break

    number = int(number)

    # If odd number
    if number % 2 != 0 :
        s += number

print(s)


Write a program to find the quadrant of a given point (x,y) (5)


Answer
# Python 3
x = int(input('Enter x coordinate of point : '))
y = int(input('Enter y coordinate of point : '))

if x == 0 or y == 0:
    print('Point is on an axis')
else:
    if x > 0:
        if y > 0:
            print('First Quadrant')
        else:
            print('Fourth Quadrant')
    else:
        if y > 0:
            print('Second Quadrant')
        else:
            print('Third Quadrant')


Write a program that reads an integer N from the keyboard and then calls a user defined function to compute and displays the sum of the numbers from N to (2N) if N is non-negative. If N is negative, then displays the sum of the numbers from (2N) to N.The starting and ending points are included in the sum. (4)


Answer
# Python 3
def sumOfRange(start, end):
    s = 0

    # end + 1 because ending point needs to be included in the sum
    for i in range(start, end + 1):
        s += i

    return s

n = int(input('Enter number : '))

# Non-negative
if n > 0:
    print(sumOfRange(n, 2*n))
else:
    # 2*n will be negative
    print(sumOfRange(2*n, n))


Write a program to compute the sum of first n positive integers using a recursive function. (4)


Answer
# Python 3
# Get the 'n'th term in the series of sum of positive numbers
def recurseSum(n):
    # 1st term and the 2nd term in the series is the term number itself
    if n == 0 or n == 1:
        return n

    return n + recurseSum(n - 1)

n = int(input('Enter a positive number : '))
print(recurseSum(n))


Write a menu driven program to calculate area of circle, triangle, rectangle and square. Use a separate function to implement each operation. (5)


Answer
# Python3
def circle():
    r = int(input('Enter radius : '))
    print('Area of circle : ', 3.14 * r * r)

def triangle():
    b = int(input('Enter base : '))
    h = int(input('Enter height : '))

    print('Area of triangle : ', 0.5 * b * h)

def rectangle():
    l = int(input('Enter length : '))
    b = int(input('Enter breadth : '))

    print('Area of rectangle : ', l * b)

def square():
    a = int(input('Enter length of square : '))
    print('Area of square : ', a * a)

print('Find Area (c = circle, t = triangle, r = rectangle, s = square)')
op = input('Enter operation : ')
if op == 'c':
    circle()
elif op == 't':
    triangle()
elif op == 'r':
    rectangle()
else:
    square()


Write a program to check if a given string is a palindrome or not, without reversing the original string (7)


Answer
# Python 3
s = input('Enter string : ')

# Assume to be palindrome
palindrome = True

for i in range(0, len(s)):
    # Check if character at position from beggining and ending are the same. If not, it's not a palindrome
    if s[i] != s[ -(i+1) ]:
        palindrome = False
        break

if palindrome == True:
    print('Palindrome')
else:
    print('Not palindrome')


Write a python program to create a dictionary of phone numbers and names of five persons. Display the contents of the dictionary in alphabetical order of names.


Answer
# Python 3
phonebook = {}

for i in range(0, 5):
    name = input('Enter name : ')
    # Phone may contain +, so receiving as string
    phone = input('Enter phone number : ')

    # Add item to dictionary
    phonebook[name] = phone

# Sort the phonebook in order of names
sortedPhonebook = sort(phonebook)

for name, phone in sortedPhonebook:
    print(name, ' - ', phone)


June 2016


Write a python code to find transpose of a matrix using list. (4)


Answer
# Python 3
matrix = []

size = int(input('Enter size of square matrix : '))

for i in range(0, size):
    matrix.append([])
    for j in range(0, size):
        matrix[i].append(int(input('Enter value in ' + str(i + 1) + 'th row and ' + str(j + 1) + 'th column : ')))

transpose = []

for i in range(0, size):
    transpose.append([])
    for j in range(0, size):
        transpose[i].append(matrix[j][i])

for i in range(0, size):
    for j in range(0, size):
        print(transpose[i][j], end=' ')
    print()


Write a python program that opens a file for input and prints the count of four letter words in it. (5)


Answer
#Python3
fp = open('file.txt', 'r')
contents = fp.read()

count = 0
# Get words by splitting string by a space
words = contents.split(' ')

for word in words:
    if len(word) == 4:
        count += 1

fp.close()

print('Number of 4 letter words: ', count)


Write a Python code to search an element in a list (3)


Answer
# Python 3
li = []

s = input('Enter element to be searched : ')

for i in range(0, len(li)):
    if li[i] == s:
        print('Found element at position ', i)


Write a Python program using function to check the type of a triangle (Scalene, Isosceles, Equilateral) by getting vertices from the user (8)


Answer
# Python3
def getPoint():
    x = int(input('Enter x coordinate : '))
    y = int(input('Enter y coordinate : '))

    # Return a tuple
    return (x, y)

# Find the distance between two points
def findDistance(centre, point):
    # centre and point is a tuple.
    # centre[0] and point[0] will have x coordinate
    xDiff = centre[0] - point[0]
    yDiff = centre[1] - point[1]

    distance = math.sqrt((xDiff ** 2) + (yDiff ** 2))

    return distance

print('Enter first point')
point1 = getPoint()
point2 = getPoint()
point3 = getPoint()

a = findDistance(point1, point2)
b = findDistance(point2, point3)
c = findDistance(point1, point3)

if a == b and b == c and a == c:
    print('Equilateral')
elif (a == b) or (b == c):
    print('Isosceles')
else:
    print('Scalene')


January 2016


Write a Python program to compute nth fibonacci number. Use a recursive function. (2)


Answer
# Python 3
def fibo(n):
    # First and second term of fibonacci series is the term numberi tself
    if n == 0 or n == 1:
        return n
    return n + fibo(n-1)

n = int(input('Enter number of terms : '))
for i in range(0, n):
    print(fibo(n))


Write a Python program to display all Armstrong numbers in a given range (5)


Answer
# Python 3
def isArmstrong(n):
    s = 0
    n = str(n)
    l = len(n)

    for digit in n:
        s += int(digit) ** l

    if int(n) == s:
        return True
    return False

start = int(input('Enter starting range : '))
end = int(input('Enter ending range : '))

for i in range(start, end):
    if isArmstrong(i):
        print(i)


Write a Python program to count number of vowels, consonants, words and questionmarks in a given string (6)


Answer
# Python 3
s = input('Enter a string :')

vowels = 0
consonants = 0
qm = 0

for l in s:
    if l.isalpha():
        if l == 'a' or l == 'e' or l == 'i' or l == 'o' or l == 'u':
            vowels += 1
        else:
            consonants += 1
    elif l == '?':
        qm += 1

words = len(s.split(' '))

print('Number of vowels : ', vowels)
print('Number of consonants : ', consonants)
print('Number of words : ', words)
print('Number of questionmarks : ', qm)