Python Programs

Author: OmkarPathak

OOP/P01_ClassDefinition.py

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+#In this program we will see how to define a class
+
+class MyFirstClass():
+    #Class Attributes
+    var = 10
+
+firstObject = MyFirstClass()
+print(firstObject)      #Printing object's memory hex
+print(firstObject.var)  #Accessing Class Attributes
+
+secondObject = MyFirstClass()
+print(secondObject)
+print(secondObject.var)

OOP/P02_InstanceMethods.py

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+#In this example we will be seeing how instance methods are used
+#Instance methods are accessed by: instance.method()
+
+class Vehicle():
+    #Class Methods/ Attributes
+
+    #Here self is passed as an argument because instance is passed as first argument
+    def type(self):     #Without self it throws an error
+        print(self)
+        print('I have a type')
+
+car = Vehicle()
+print(car)
+car.type()

OOP/P03_InstanceAttributes.py

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+#In this example we will be seeing how instance Attributes are used
+#Instance attributes are accessed by: object.attribute
+#Attributes are looked First in the instance and THEN in the class
+
+import random
+class Vehicle():
+    #Class Methods/ Attributes
+    def type(self):
+        #NOTE: This is not a class attribute as the variable is binded to self. Hence it becomes
+        #instance attribute
+        self.randomValue = random.randint(1,10) #Setting the instance attribute
+
+car = Vehicle()
+car.type()              #Calling the class Method
+print(car.randomValue)  #Calling the instance attribute

OOP/P04_InitConstructor.py

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+#This example shows the use of __init__ constructor
+
+class Vehicle():
+    #__init__ is used to set values as soon as new object are created
+    #__init__ is a keyword hence it has to be named like it is
+    def __init__(self):     #called automatically hence known as magic method
+        print('Calling init')
+        self.val = 0
+        self.cost = 10000   #Setting the default value when the object is created
+
+    def incrementVehicle(self):
+        self.val += 1
+
+
+car = Vehicle()     #__init__ is called
+print('First obj value:',car.val)
+car.incrementVehicle()
+car.incrementVehicle()
+print('First obj value after incrementing:',car.val)      #2
+
+bike = Vehicle()       #__init__ is called makes val 0 for this ANOTHER instance
+print('Second obj value:',bike.val)

OOP/P05_FirstProgramusingOOP.py

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+#In this assignment we would see the use of OOP
+
+class MaxSizeList(object):
+    def __init__(self, value):
+        self.myList = []
+        self.value = value
+
+    def push(self, String):
+        try:
+            String = str(String)
+            self.myList.append(String)
+        except ValueError:
+            print('You can only push strings!')
+
+    def getList(self):
+        print(self.myList[-self.value:])
+
+if __name__ == '__main__':
+    a = MaxSizeList(3)
+    b = MaxSizeList(1)
+
+    a.push('Hey')
+    a.push('Hello')
+    a.push('Hi')
+    a.push('Let\'s')
+    a.push('Go')
+
+    b.push('Hey')
+    b.push('Hello')
+    b.push('Hi')
+    b.push('Let\'s')
+    b.push('Go')
+
+    a.getList()
+    b.getList()

OOP/P06_Inheritance.py

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+#This program illustrates the concept of inheritance
+#Python looks up for method in following order: Instance attributes, class attributes and the
+#from the base class
+
+class Data(object):
+    def getData(self):
+        print('In data!')
+
+class Time(Data):           #Inhertiting from Data class
+    def getTime(self):
+        print('In Time!')
+
+if __name__ == '__main__':
+    data = Data()
+    time = Time()
+
+    data.getData()
+    time.getTime()
+    time.getData()          #Inherted Data method

OOP/P07_MoreOnInheritance.py

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+#This program illustrates the advanced concepts of inheritance
+#Python looks up for method in following order: Instance attributes, class attributes and the
+#from the base class
+#mro: Method Resolution order
+
+class Data(object):
+    def __init__(self, data):
+        self.data = data
+
+    def getData(self):
+        print('Data:',self.data)
+
+class Time(Data):           #Inhertiting from Data class
+    def getTime(self):
+        print('Time:',self.data)
+
+if __name__ == '__main__':
+    data = Data(10)
+    time = Time(20)     #inherited Class -> Value passed to __init__of Data (Base class)
+
+    time.getTime()
+    data.getData()
+    time.getData()
+
+    print(Time.mro())

OOP/P08_MultipleInheritence.py

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+#This program shows the order in which the classes are accessed in case of multiple inheritance
+#Python uses DEPTH FIRST SEARCH algorithm for lookups
+
+class A(object):
+    def doThis(self):
+        print('Doing this in A')
+
+class B(A):
+    pass
+
+#If class C was also eing derived from A then the lookup order would be D,B,C,A
+class C(object):
+    def doThis(self):
+        print('Doing this in C')
+
+class D(B, A):
+    pass
+
+if __name__ == '__main__':
+    dObj = D()
+    dObj.doThis() #A method gets called because order for lookup is D,B,A,C this is shown by function mro
+
+    print(D.mro())

Programs/P01_hello.py

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+#This program prints the entered message
+
+def justPrint(text):
+    '''This function prints the text passed as argument to this function'''
+    print(text)
+
+if __name__ == '__main__':
+    justPrint('Hello')

Programs/P02_VariableScope.py

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+#This programs shows the rules for variable scope
+
+# LEGB Rule: Local, Enclosing, Global, Built-in
+
+x = 'Global x'
+
+def test():
+    #global x
+    y = 'Local y'
+    x = 'Local x'
+    print(x +', '+ y) #prints 'Local x' and  'Local y'
+
+if __name__ == '__main__':
+    test()
+    print(x) #prints 'Global x'

Programs/P03_ListsOperations.py

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+#This program gives examples about various list operations
+
+#Syntax: list[start: end: step]
+
+myList = [1, 2, 3, 4, 5, 6, 7, 8, 9]
+#index    0  1  2  3  4  5  6  7  8
+#        -9 -8 -7 -6 -5 -4 -3 -2 -1
+
+#List Slicing
+print('Original List:',myList)
+print('First Element:',myList[0]) #Prints the first element of the list or 0th element of the list
+print('Element at 2nd Index position:',myList[2]) #Prints the 2nd element of the list
+print('Elements from 0th Index to 4th Index:',myList[0: 5]) #Prints elements of the list from 0th index to 4th index. IT DOESN'T INCLUDE THE LAST INDEX
+print('Element at -7th Index:',myList[-7]) #Prints the -7th or 3rd element of the list
+
+#To append an element to a list
+myList.append(10)
+print('Append:',myList)
+
+#To find the index of a particular element
+print('Index of element \'6\':',myList.index(6)) #returns index of element '6'
+
+#To sort the list
+myList.sort()
+
+#To pop last element
+print('Poped Element:',myList.pop())
+
+#To remove a particular element from the lsit BY NAME
+myList.remove(6)
+print('After removing \'6\':',myList)
+
+#To insert an element at a specified Index
+myList.insert(5, 6)
+print('Inserting \'6\' at 5th index:',myList)
+
+#To count number of occurences of a element in the list
+print('No of Occurences of \'1\':',myList.count(1))
+
+#To extend a list that is insert multiple elemets at once at the end of the list
+myList.extend([11,0])
+print('Extending list:',myList)
+
+#To reverse a list
+myList.reverse()
+print('Reversed list:',myList)

Programs/P10_LCM.py

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+#This program calculates the LCM of the two numbers entered by the user
+
+def LCM(number1, number2):
+    '''This function calculates LCM of two numbers inputed by the user'''
+    maximum = max(number1, number2)
+    i = maximum
+    while True:
+        if (i % number1 == 0  and i % number2 == 0):
+            lcm = i
+            break
+        i += maximum
+
+    return lcm
+
+if __name__ == '__main__':
+    userInput1 = int(input('Enter first number: '))
+    userInput2 = int(input('Enter second number: '))
+    print('LCM of {} and {} is {}'.format( userInput1, userInput2, LCM(userInput1, userInput2)))

Programs/P11_BinaryToDecimal.py

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+#This program converts the given binary number to its decimal equivalent
+
+def binaryToDecimal(binary):
+    '''This function calculates the decimal equivalent to given binary number'''
+    binary1 = binary
+    decimal, i, n = 0, 0, 0
+    while(binary != 0):
+        dec = binary % 10
+        decimal = decimal + dec * pow(2, i)
+        binary = binary//10
+        i += 1
+    print('Decimal equivalent of {} is {}'.format(binary1, decimal))
+
+if __name__ == '__main__':
+    userInput = int(input('Enter the binary number to check its decimal equivalent: '))
+    binaryToDecimal(userInput)

Programs/P12_DecimalToBinary.py

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+#Program to convert decimal to its equivalent binary
+
+def decimalToBinary(n):
+   '''Function to print binary number for the input decimal using recursion'''
+   if n > 1:
+       decimalToBinary(n//2)
+   print(n % 2,end = '')
+
+if __name__ == '__main__':
+    userInput = int(input('Enter the decimal number to find its binary equivalent: '))
+    decimalToBinary(userInput)
+    print()

Programs/P13_Palindrome.py

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+#This program checks for the palindrome
+
+def palindrome(string):
+    '''This function checks the string for palindrome'''
+    revString = string[::-1]
+    if string == revString:
+        print('String is Palindrome')
+    else:
+        print('String is not Palindrome')
+
+if __name__ == '__main__':
+    userInput = str(input('Enter a string to check for Palindrome: '))
+    palindrome(userInput)

Programs/P14_CheckGreater.py

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+#This prpgram checks that the given number is greater than all those numbers in th list
+
+def checkGreater(number):
+    '''This function checks whether the entered number is greater than those in the list'''
+    original = [1,2,3,4,5]
+    original.sort()
+    if number > original[-1]:
+        print('Yes, the entered number is greater than those in the list')
+    else:
+        print('No, entered number is less than those in the list')
+
+if __name__ == '__main__':
+    userInput = int(input('Enter the number to check: '))
+    checkGreater(userInput)

Programs/P15_Arguments.py

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+#This program gives a demo of how can you pass arguments while running python programs
+#Run the program as: python P15_Arguments.py Omkar Pathak
+
+import sys
+
+def arguments():
+    '''This function prints the argruments passed while running the python program'''
+    try:
+        print('This is the name of the script:', sys.argv[0])
+        print('First argument:', sys.argv[1])
+        print('Second argument:', sys.argv[2])
+    except IndexError:
+        print('Give only two arguments')
+
+if __name__ == '__main__':
+    arguments()

Programs/P16_CountVowels.py

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+#This program counts the vowels present in the user input
+
+def countVowels(sentence):
+    '''This function counts the vowels'''
+    count = 0
+    sentence = sentence.lower()
+    for c in sentence:
+        if c in ['a', 'e', 'i', 'o', 'u']:
+            count += 1
+    return count
+
+
+if __name__ == '__main__':
+    userInput = str(input("Enter the string to check for vowels: "))
+    count = countVowels(userInput)
+    print('Vowel Count: ',count)

Programs/P17_EvenOdd.py

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+ #This program takes input from user and sorts the numbers in two arrays, one of even and other of odd
+
+def evenOdd(numbers):
+    '''This function divides the numbers in two arrays one of even and other of odd'''
+    even = []
+    odd = []
+    for number in numbers:
+        if int(number) % 2 == 0:
+            even.append(number)
+        else:
+            odd.append(number)
+    return even, odd
+
+if __name__ == '__main__':
+    userInput = input("Enter the numbers (space separated) to check: ")
+    userInput = list(userInput.split())
+    even, odd = evenOdd(userInput)
+    print('Even Nos: ', ','.join(even), '\n', 'Odd Nos: ', ','.join(odd))

Programs/P18_Logging.py

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+#This program illustrates a logging example
+import logging
+
+def log(number):
+    ''' This function creates a log file if any error is reported '''
+    logging.basicConfig(filename = 'P18-logfile.txt', level = logging.INFO)
+    try:
+        if int(number) % 2 == 0:
+            print('Successful')
+        else:
+            print('Unsuccessful, this instance will be reported, check the log file')
+            logging.info('Invalid Entry')
+    except:
+        print('Please enter a valid integer')
+
+if __name__ == '__main__':
+    try:
+        userInput = int(input('Enter a number: '))
+        log(userInput)
+    except:
+        print('Please enter a valid integer')