.Please post answer who is expert in Python!! so I wanna answers of Python OOP e
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Question
.Please post answer who is expert in Python!! so I wanna answers of Python OOP experts
And I wanna detailed answers
Define what a reference to an object means in the context of Python programming and explain what using a reference entails. You may wish to provide examples to make your point clearer, but make sure you describe the idea first. So This question was also about the fundamental concept of programming, regarding references to objects/variable Which object-oriented programming concept is employed as a code reuse mechanism? Name this concept and describe it. This question did NOT ask for the explanation of what code reuse is. It asked about the name of the OOP concept that provides for. codeand how that concept allows for code reuse. Explain what a decorator is in the context of Python. Describe at least one advantageof using decorators. At least two advantage not one Explain what the singleton pattern is. Explain if this pattern is necessary in the context of Python object-oriented programming and how it may be implemented in Python.Explanation / Answer
ANS1-> Object A unique instance of a data structure that's defined by its class. An object comprises both data members (class variables and instance variables) and methods.Like Student,Teacher etc.
variable A variable that is defined and only refer to the current instance of a class,to hold data temporarily for that moment only.
Eg: class Employee://class
'Common base class for all employees'
empCount = 0//variable
def displayCount(self):
print "Total Employee %d" % Employee.empCount……so on.
ANS2-> “Inheritance” is the Concept of OOPS that provides code reusability. Inheritance is a mechanism in which one object acquires all the properties and behaviours of the parent object without writing that parent code in child class. Inheritance allows programmers to create classes that are built upon existing classes , to specify a new implementation to maintain the same behaviour and this can be done by inheritance only by reusing implementation and by establishing a syntactic relationship.
ANS 3-> Python decorators are to add functionality to an existing code which as a part of the program tries to modify another part of the program at compile time.
ADVANTAGES:
1.This supports more readability to the applications.
2. It is very easy to use, a decorator can handle Analytics, logging, and instrumentation very readably and easily.
ANS 4-> The singleton pattern is a pattern that restricts the instantiation of a class to one object. Yes, it is necessary when exactly one object is needed to coordinate actions across the system.
Eg: class Singleton:
""" A python singleton """
class __impclass:
""" Implementation of the singleton interface """
def spam(self):
""" Test method, return singleton id """
return id(self)
# storage for the instance reference
__instance = None
def __init__(self):
""" Create singleton instance """
# Check whether we already have an instance
if Singleton.__instance is None:
# Create and remember instance
Singleton.__instance = Singleton.__impclass()
# Store instance reference as the only member in the handle
self.__dict__['_Singleton__instance'] = Singleton.__instance
def __getattr__(self, attr):
""" Delegate access to implementation """
return getattr(self.__instance, attr)
def __setattr__(self, attr, value):
""" Delegate access to implementation """
return setattr(self.__instance, attr, value)
# Test it
s1 = Singleton()
print id(s1), s1.spam()
s2 = Singleton()
print id(s2), s2.spam()
# Sample output, the second (inner) id is constant:
# 8172684 8176268
# 8168588 8176268
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