Class and Object | Python

 

P1 / CLASS WITH PUBLIC ATTRIBUTES

Create a class named Person with the following 2 public attributes.

name

age

 

Include a constructor .

__init__(self,name, age)

 

Create an object of class Person to test the above class.

 

Input and Output Format:

Refer Sample Input and Output for formatting specifications.

 

Sample Input and Output:

[All text in bold corresponds to input and the rest corresponds to output]

 

Enter name

Mahirl

Enter age

10

Person Details

Mahirl

10


Additional Sample TestCases

Sample Input and Output 1 :
Enter name
Mahirl
Enter age
10
Person Details
Mahirl
10


P2 / CLASS WITH PRIVATEATTRIBUTES

Create a class named Person with the following 2 private attributes.

__name

__age

 

Include a constructor .

___init__(self,name, age)

 

Include a method

display()

In this method, display the person details in the format specified in the sample output.

 

Create an object of class Person and invoke the display method to test the above class.

Note : The output statement "Person Details" is in the Main.py file.

Input and Output Format:

Refer Sample Input and Output for formatting specifications.

 

Sample Input and Output:

[All text in bold corresponds to input and the rest corresponds to output]

 

Enter name

Mahirl

Enter age

10

Person Details

Mahirl

10


Additional Sample TestCases

Sample Input and Output 1 :
Enter name
Mahirl
Enter age
10
Person Details
Mahirl
10


P3 / __STR__ METHOD

Create a class named Person with the following 2 private attributes.

__name

__age

 

Include a constructor .

___init__(self,name, age)

 

Include a method

__str__(self)

This method returns a string corresponding to person details in the format specified in the sample output.

 

Create an object of class Person to test the above class.

 

Note:

The __str__ method is useful for a string representation of the object, either when someone codes in str(your_object), or even when someone might do print(your_object).

 

Input and Output Format:

Refer Sample Input and Output for formatting specifications.

[All text in bold corresponds to input and the rest corresponds to output]

 

Sample Input and Output:

Enter name

Mahirl

Enter age

10

Person Details

Mahirl is 10 years old

 



P4 / MODIFIED PERSON CLASS

Create a class named Person with the following 4 private attributes.

__first_name
__last_name
__age
__email

Include a constructor .
___init__(self,first_name, last_name,age)
    email is formed by concatenating the first name, last name and gmail.com in the format
     specified in the output.

Include a method
__str__(self)
    This method returns a string corresponding to person details in the format specified in the
     sample output.
fullname(self)
    This method returns the full name of the person as a concatenation of first name and last name
     separated by a space.

Create an object of class Person to test the above class.


Input and Output Format:
Refer Sample Input and Output for formatting specifications.

Sample Input and Output:
[All text in bold corresponds to input and the rest corresponds to output]

Enter first name
Mahirl
Enter last name
Malar
Enter age
10
Full name of the person is  Mahirl Malar
Person Details
Mahirl Malar is 10 years old and her email id is Mahirl.Malar@gmail.com




P5 / CLASS VARIABLE

Create a class named Person with the following 4 private attributes.

__first_name
__last_name
__age
__email

Include a class variable named domain_name in the Person class.
    This domain_name is used for generating the email id.

Include a constructor .
___init__(self,first_name, last_name,age)
    email is formed by concatenating the first name, last name and with given domain name in the format
     specified in the output.

Include a method
__str__(self)
    This method returns a string corresponding to person details in the format specified in the
     sample output.
fullname(self)
    This method returns the full name of the person as a concatenation of first name and last name
     separated by a space.

Create an object of class Person to test the above class.

Note:
Class or static variables are shared by all objects. Instance or non-static variables are different for different objects (every object has a copy of it).

In C++ and Java, we can use static keyword to make a variable as class variable. The variables which don’t have preceding static keyword are instance variables.

The Python approach is simple, it doesn’t require a static keyword. All variables which are assigned a value in class declaration are class variables. And variables which are assigned values inside class methods are instance variables.


Input and Output Format:
Refer Sample Input and Output for formatting specifications.

Sample Input and Output:
[All text in bold corresponds to input and the rest corresponds to output]

Enter domain name
amphi@in
Enter details of first person
Enter first name
Mahirl
Enter last name
Malar
Enter age
10
Enter details of second person
Enter first name
Madhu
Enter last name
Kavi
Enter age
15
First Person Details
Full name of the person is  Mahirl Malar
Mahirl Malar is 10 years old and her email id is Mahirl.Malar@amphi@in
Second Person Details
Full name of the person is  Madhu Kavi
Madhu Kavi is 15 years old and her email id is Madhu.Kavi@amphi@in




P6 / LIST OF OBJECTS

Create a class named Person with the following 4 private attributes.

__first_name
__last_name
__age
__email

Incude a class variable named domain_name in the Person class.
    This domain_name is used for generating the email id.
Incude a class variable named counter in the Person class.
    counter is used for keeping track of the number of objects created.

Include a constructor .
__init__(self,first_name, last_name,age)
    email is formed by concatenating the first name, last name and with domain name in the format
     specified in the output.
    Class variable counter is incremented by 1.

Include a method
__str__(self)
    This method returns a string corresponding to person details in the format specified in the
     sample output.
fullname(self)
    This method returns the full name of the person as a concatenation of first name and last name
     separated by a space.

Use property  and setter decorator for the attribute age. 

Create multiple objects of the person class and  test the above class.

Note:
The following code uses the built-in @property decorator to define the x property in the C class. 

Example:
class C :
    def __init__(self):
        self.__x = None

    @property
    def x(self):
        return self.__x

    @x.setter
    def x(self, value):
        self.__x = value
The x(self) function is marked with the @property decorator which indicates that the x(self) method is a getter method and the name of the property is the method name only, in this case x. Now, x(self, value) is assigning a value to the private attribute __x. So, to mark this method as a setter method for the x property, the @x.setter decorator is applied. This is how we can define a property and its getter and setter methods. 

Input and Output Format:
Refer Sample Input and Output for formatting specifications.

Sample Input and Output:
[All text in bold corresponds to input and the rest corresponds to output]

Enter domain name
amphi.in
Enter details of person
Enter first name
Mahirl
Enter last name
Malar
Enter age
10
Do you want to add the details of another person? Type yes/no
yes
Enter details of person
Enter first name
Banu
Enter last name
Kumar
Enter age
25
Do you want to add the details of another person? Type yes/no
yes
Enter details of person
Enter first name
Chandra
Enter last name
Kala
Enter age
50
Do you want to add the details of another person? Type yes/no
no
Number of person objects created
 3
List Person Details

Full name of the person is  Mahirl Malar
Mahirl Malar is 10 years old and her email id is Mahirl.Malar@amphi.in


Full name of the person is  Banu Kumar
Banu Kumar is 25 years old and her email id is Banu.Kumar@amphi.in


Full name of the person is  Chandra Kala
Chandra Kala is 50 years old and her email id is Chandra.Kala@amphi.in


Update Person Details
Enter the full name of the person whose details are to be updated
Mahirl Malar
Old age :  10
Enter age
11
Updated Person Details :
Mahirl Malar is 11 years old and her email id is Mahirl.Malar@amphi.in





P7 / CLASS METHOD

Create a class named Person with the following 2 private attributes.

__name

__age

Include a constructor .

___init__(self,name, age)

Include a method

__str__(self)

This method returns a string corresponding to person details in the format specified in the sample output.

Include a class method

from_string(cls, person_str)

This method creates and returns an object of Person class from a string. This method accepts a class variable and a string. String contains the values for name and age in a comma separated format.

Create objects of class Person to test the above class.

Note:

A class method is one that belongs to the class as a whole. It doesn't require an instance. Instead, the class will automatically be sent as the first argument. A class method is declared with the @classmethod decorator.

Input and Output Format:

Refer Sample Input and Output for formatting specifications.

Sample Input and Output:

[All text in bold corresponds to input and the rest corresponds to output]

Creating object using __init__ method

Enter name

Mahirl

Enter age

10

Person Details

Mahirl is 10 years old

Creating object using class method

Enter name and age in comma separated format

Chandra,40

Person Details

Chandra is 40 years old





P8 / STATIC METHOD

Create a class named Person with the following 3 private attributes.

__name

__age

__id

Include a class variable named counter and initialize its value to 0.

Include a constructor .

___init__(self,name, age)

Generate the value for id attribute from the counter.  The id should be unique for every person and it should be sequential.

Include a method

__str__(self)

This method returns a string corresponding to person details in the format specified in the sample output.

Include a class method

from_string(cls, person_str)

This method creates and returns an object of Person class from a string. This method accepts a class variable and a string. String contains the values for name and age in a comma separated format.

Include a static method

initialize_counter(value)

This method is used to set the value of the class variable counter.

Create objects of class Person to test the above class.

Note:

Static Methods:

  • Simple functions with no self argument.

  • Work on class attributes; not on instance attributes.

  • Can be called through both class and instance.

  • The decorator @staticmethod is used to create them.

Input and Output Format:

Refer Sample Input and Output for formatting specifications.

Sample Input and Output:

[All text in bold corresponds to input and the rest corresponds to output]

Enter starting value of counter

100

Creating object using __init__ method

Enter name

Mahirl

Enter age

10

Person Details

Mahirl is 10 years old and her id is 101

Creating object using class method

Enter name and age in comma separated format

Devi,40

Person Details

Devi is 40 years old and her id is 102






P9 / CHECK FOR OBJECT EQUALITY

Create a class named Person with the following 2 private attributes.

__name

__age

 

Include a constructor .

___init__(self,name, age)

 

Include a method

__str__(self)

This method returns a string corresponding to person details in the format specified in the sample output.

 

Include a comparison method

def __eq__(self,other)

This method should returns true if both the objects have the same attribute values.

 

Create objects of class Person to test the above class.

 

Note :

Perform case-sensitive comparison

 

Input and Output Format:

Refer Sample Input and Output for formatting specifications.

[All text in bold corresponds to input and the rest corresponds to output]

 

Sample Input and Output 1:

Person1

Enter name

Mahirl

Enter age

10

Person Details

Mahirl is 10 years old

 

 

Person2

Enter name

Mahirl

Enter age

15

Person Details

Mahirl is 15 years old

 

 

Check For Equality

Person1 and Person2 are not equal

 

Sample Input and Output 2:

Person1

Enter name

Mahirl

Enter age

10

Person Details

Mahirl is 10 years old

 

 

Person2

Enter name

Mahirl

Enter age

10

Person Details

Mahirl is 10 years old

 

 

Check For Equality

Person1 and Person2 are equal








P10 / ONE TO ONE RELATIONSHIP – 1

P10 / One to One Relationship – 1

Create a class named Address with the following private_attributes

__street

__city

__state

 

Include a constructor

__init__(self, street, city, state)

 

Include a method

__str__(self)

This method returns a string corresponding to Address details in the format specified

in the sample output.

 

Create a class named Person with the following private_attributes

__name

__age

__address (of type Address)

 

Include a constructor

__init__(self, name, age, address)

 

Include a method

__str__(self)

This method returns a string corresponding to Person details in the format specified

in the sample output.

 

Create objects of the above classes and test them.

 

Input and Output Format:

Refer Sample Input and Output for formatting specifications.

 

Sample Input and Output 1:

[All text in bold corresponds to input and the rest corresponds to output]

 

Enter name

Mahirl

Enter age

10

Enter address

Enter street

LMC Street

Enter city

Salem

Enter state

Tamilnadu

Person Details

Mahirl is a person who is 10 years old and lives in the following address : LMC Street , Salem , Tamilnadu

 





P12 / ONE TO MANY RELATIONSHIP

Create a class named City with the following private_attributes

__name

__state (of type State)

 

Include a constructor

__init__(self, name, state)

 

Include a method

__str__(self)

This method returns a string corresponding to City details in the format specified

in the sample output.

 

Create a class named State with the following private_attributes

__name

__city_list (of type City)

 

Include a constructor

__init__(self, name, city_list)

 

Include a method

__str__(self)

This method returns a string corresponding to State details in the format specified in the sample output.

 

Include @property decorator for name

Include @property decorator for city_list

Include @setter decorator for city_list

 

Create objects of the above classes and test them.


Note :
Perform case-sensitive string comparison.
Initially state_list have the below states.

Tamilnadu
Andhra
Karnataka
Kerala

If any new state is added other than the state in the list, it must be added to the state_list. [Refer sample input and output]
 

Input and Output Format:

Refer Sample Input and Output for formatting specifications.

[All text in bold corresponds to input and the rest corresponds to output]

 

Sample Input and Output 1:

Enter City Details

Enter city name

Coimbatore

Enter state name

Tamilnadu

Do you want to add another city? Type Yes / No

Yes

Enter city name

Chennai

Enter state name

Tamilnadu

Do you want to add another city? Type Yes / No

Yes

Enter city name

Bangalore

Enter state name

Karnataka

Do you want to add another city? Type Yes / No

Yes

Enter city name

Vijayawada

Enter state name

Andhra

Do you want to add another city? Type Yes / No

Yes

Enter city name

Cochin

Enter state name

Kerala

Do you want to add another city? Type Yes / No

Yes

Enter city name

Bhopal

Enter state name

Madhya Pradesh

Do you want to add another city? Type Yes / No

No

 

City Details

 

Coimbatore is in state Tamilnadu

Chennai is in state Tamilnadu

Bangalore is in state Karnataka

Vijayawada is in state Andhra

Cochin is in state Kerala

Bhopal is in state Madhya Pradesh

 

State Details

 

Tamilnadu has 2 cities

Andhra has 1 cities

Karnataka has 1 cities

Kerala has 1 cities

Madhya Pradesh has 1 cities

 




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