Question

1. Pleae write the following code in Python 3. Also, please show all the outputs.

. Write a simple Rectangle class. It should do the following:

Accepts length and width as parameters when creating a new instance

Has a perimeter method that returns the perimeter of the rectangle

Has an area method that returns the area of the rectangle

Don't worry about coordinates or negative values, etc.

Python provides several modules to allow you to easily extend some of the basic objects in the language. Among these modules are UserDict, UserList, and UserString. (Refer to the chart in Topic 10.3 to see what the methods you need to override look like. Also, since UserDict and UserList are part of the collection module, you can import them using from collections import UserDict and from collections import UserList.)

2. Using the UserList module, create a class called Ulist, and override the __add__, append, and extend methods so that duplicate values will not be added to the list by any of these operations.

3. (Extra Credit) Using the UserDict module, create a class called Odict, which will be just like a dictionary but will "remember" the order in which key/value pairs are added to the dictionary. (Hint: Override the built-in __setitem__method.) Create a new method for the Odict object called okeys, which will return the ordered keys.

Answer 1

1. Rectangle Class in python3, this will return area and perimeter:

class Rectangle:
        def __init__(self,length,width):
                self.length=length
                self.width=width
        def perimeter(self):
                perimeter_value= 2*(self.length+self.width)
                return perimeter_value
        def area(self):
                return self.length*self.width
rect_obj=Rectangle(5,10)
print("The perimeter of rectangle is: ",rect_obj.perimeter())
print("The are of rectangle is: ",rect_obj.area())

Output: length =5 and width=10

2 &3) UserDict and UserList:

from collections import UserDict

class Odict(UserDict):
    def __init__(self, data = {}, **kw):
        UserDict.__init__(self)
        self.update(data)
        self.update(kw)
        self.keylist = []

    def __setitem__(self,key,value):
        self.data[key] = value
        self.keylist.append(key)

    def okeys(self):
        return self.keylist

myDict = Odict()
myDict['d'] = 'value5'
myDict['a'] = 'value4'
myDict['e'] = 'value6'

print(myDict.okeys())

from collections import UserList
class Ulist(UserList):
    def __init__(self, data = [], **kw):
        UserList.__init__(self)
        self.data = data

    def __add__(self, newvalue):
        for item in newvalue:
            if item in self.data:
                print ("%r already exists, not adding." % item)
            else:
                self.data += [item]
        return self.data

    def append(self,newvalue = None):
        if newvalue in self.data:
            print ("%r already exists, not adding." % newvalue)
        else:
            return self.data.append(newvalue)

    def extend(self, newvalue = []):
        for item in newvalue:
            if item in self.data:
                print ("%r already exists, not adding." % item)
            else:
                return self.data.extend(item)
        return self.data

mylist = Ulist([1,2,3])
#mylist.__add__([5,6])
#mylist.append('a')
#mylist.append([3])
#mylist.extend([1,2,3,'a'])
print( mylist)

output:

you can give inputs in program or you can uncomment few inputs above