Added OOP's and Comprehension Programs

Author: rahulhgdev

Beginner_Level/Class.py

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+class Human:
+    def __init__(self, n, o):
+        self.name = n
+        self.occupation = o
+
+    def do_work(self):
+        if self.occupation == "Tennis Player":
+            print(self.name,"plays tennis")
+        elif self.occupation == "Cricket Player":
+            print(self.name,"Plays Cricket")
+
+    def speak(self):
+        print(self.name,"\nsay how are you?")
+
+sachin = Human("Sachin Tendulkar","Cricker")
+sachin.do_work()
+sachin.speak()
+
+print('\n')
+
+maria = Human("Maria sharapova","Tennis")
+sachin.do_work()
+sachin.speak()
+
+print('\n')
+
+
+# built-in class modules
+
+class Employee:
+    'Common base class for all employees'
+    empCount = 0
+
+    def __init__(self, name, salary):
+        self.name = name
+        self.salary = salary
+        Employee.empCount += 1
+
+    def displayCount(self):
+        print("Total Employee %d" % Employee.empCount)
+
+    def displayEmployee(self):
+        print("Name : ", self.name, ", Salary: ", self.salary)
+
+
+print("Employee.__doc__:", Employee.__doc__)
+print("Employee.__name__:", Employee.__name__)
+print("Employee.__module__:", Employee.__module__)
+print("Employee.__bases__:", Employee.__bases__)
+print("Employee.__dict__:", Employee.__dict__)

Beginner_Level/Inheritance.py

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+class Vehicle:
+    def genral_usage(self):
+        print("use for transportation")
+
+class Car(Vehicle):
+    def __init__(self):
+        print("I'm a car")
+        self.wheels = 4
+        self.has_roof = True
+
+    def specific_usage(self):
+        self.genral_usage()
+        print("specific usage: commute to work, vacation with family")
+
+class Motorcycle(Vehicle):
+    def __init__(self):
+        print("I'm a Motorcycle")
+        self.wheels = 2
+        self.has_roof = False
+
+    def specific_usage(self):
+        self.genral_usage()
+        print("specific usage: road trip, racing")
+
+c = Car()
+#c.genral_usage()   # if you don't want to call general_usage() explicitly, you can call inside class as above
+c.specific_usage()
+print('\n')
+m = Motorcycle()
+#m.genral_usage()
+m.specific_usage()
+
+print('\n')
+
+print(isinstance(c,Car))               # check and return bool value
+print(isinstance(c,Motorcycle))
+
+print('\n')
+
+# another example
+
+class Parent:        # define parent class
+   parentAttr = 100
+   def __init__(self):
+      print("Calling parent constructor")
+
+   def parentMethod(self):
+      print('Calling parent method')
+
+   def setAttr(self, attr):
+      Parent.parentAttr = attr
+
+   def getAttr(self):
+      print("Parent attribute :", Parent.parentAttr)
+
+class Child(Parent): # define child class
+   def __init__(self):
+      print("Calling child constructor")
+
+   def childMethod(self):
+      print('Calling child method')
+
+c = Child()          # instance of child
+c.childMethod()      # child calls its method
+c.parentMethod()     # calls parent's method
+c.setAttr(200)       # again call parent's method
+c.getAttr()          # again call parent's method
+
+print('\n')
+
+# method overriding
+
+class Parent:        # define parent class
+   def myMethod(self):
+      print('Calling parent method')
+
+class Child(Parent): # define child class
+   def myMethod(self):
+      print('Calling child method')
+
+c = Child()          # instance of child
+c.myMethod()         # child calls overridden method
+
+print('\n')
+
+# Multiple Inheritance
+
+class Father:
+    def skills(self):
+        print("Gardening & Programming")
+
+class Mother:
+    def skills(self):
+        print("cooking & art")
+
+class child(Father,Mother):
+    def skills(self):
+        Father.skills(self)
+        Mother.skills(self)
+        print("sports & gaming")
+
+c = child()
+c.skills()
+

Beginner_Level/List,Set&Dictionary_Comprehension.py

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+Python 3.9.0 (tags/v3.9.0:9cf6752, Oct  5 2020, 15:34:40) [MSC v.1927 64 bit (AMD64)] on win32
+Type "help", "copyright", "credits" or "license()" for more information.
+>>> numbers = [1,2,3,4,5,6,7,8,9]
+>>> even = []
+>>> for i in numbers:
+	if i%2==0:
+		even.append(i)
+
+		
+>>> even
+[2, 4, 6, 8]
+>>> # syntax [output for-loop condition]
+>>> even = [i for i in numbers if i%2==0]
+>>> even
+[2, 4, 6, 8]
+>>> cube_numbers = [i*i*i for i in numbers]
+>>> cube_numbers
+[1, 8, 27, 64, 125, 216, 343, 512, 729]
+>>> 
+>>> 
+>>> 
+>>> 
+>>> 
+>>> # Set Comprehension
+>>> s = set{[1,2,3,4,5,2,3]}
+SyntaxError: invalid syntax
+>>> s = set([1,2,3,4,5,2,3])
+>>> s
+{1, 2, 3, 4, 5}
+>>> type(s)
+<class 'set'>
+>>> even = { i for in s if i%2==0}
+SyntaxError: invalid syntax
+>>> even
+[2, 4, 6, 8]
+>>> 
+>>> 
+>>> 
+>>> 
+>>> # Dictionary Comprehension
+>>> 
+>>> cities = ["Mumbai","new york","tokyo"]
+>>> country = ["India","USA","Japan"]
+>>> z = zip(cities,country)
+>>> z
+<zip object at 0x00000253A2C7BF00>
+>>> for a in z:
+	print(a)
+
+	
+('Mumbai', 'India')
+('new york', 'USA')
+('tokyo', 'Japan')
+>>> d = {city:country for city, country in zip(cities,country)}
+>>> d
+{'Mumbai': 'India', 'new york': 'USA', 'tokyo': 'Japan'}
+>>> type(d)
+<class 'dict'>
+>>> dir(d)
+['__class__', '__class_getitem__', '__contains__', '__delattr__', '__delitem__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__ior__', '__iter__', '__le__', '__len__', '__lt__', '__ne__', '__new__', '__or__', '__reduce__', '__reduce_ex__', '__repr__', '__reversed__', '__ror__', '__setattr__', '__setitem__', '__sizeof__', '__str__', '__subclasshook__', 'clear', 'copy', 'fromkeys', 'get', 'items', 'keys', 'pop', 'popitem', 'setdefault', 'update', 'values']
+>>> 

Beginner_Level/Polymorphism.py

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+class India():
+    def capital(self):
+        print("New Delhi is the capital of India.")
+
+    def language(self):
+        print("Hindi is the most widely spoken language of India.")
+
+    def type(self):
+        print("India is a developing country.")
+
+
+class USA():
+    def capital(self):
+        print("Washington, D.C. is the capital of USA.")
+
+    def language(self):
+        print("English is the primary language of USA.")
+
+    def type(self):
+        print("USA is a developed country.")
+
+
+obj_ind = India()
+obj_usa = USA()
+for country in (obj_ind, obj_usa):
+    country.capital()
+    country.language()
+    country.type()