Python supports object-oriented programming through classes, objects, and related concepts like inheritance, polymorphism, and encapsulation. A class acts as a blueprint to create object instances. Objects contain data fields and methods. Inheritance allows classes to inherit attributes and behaviors from parent classes. Polymorphism enables the same interface to work with objects of different types. Encapsulation helps protect data by restricting access.
The document discusses various advanced Python concepts including classes, exception handling, generators, CGI, databases, Tkinter for GUI, regular expressions, and email sending using SMTP. It covers object-oriented programming principles like inheritance, encapsulation, and polymorphism in Python. Specific Python concepts like creating and accessing class attributes, instantiating objects, method overloading, operator overloading, and inheritance are explained through examples. The document also discusses generator functions and expressions for creating iterators in Python in a memory efficient way.
The document discusses object-oriented programming concepts in Python like classes, objects, methods, variables, inheritance and polymorphism. It provides examples of how to define a class with attributes and methods, create objects, and access variables and call methods. It also explains different types of methods like instance methods, class methods, static methods and variable types like instance and static/class variables. Inheritance allows creating new classes from existing classes for code reusability.
The document introduces Python modules and importing. It discusses three formats for importing modules: import somefile, from somefile import *, and from somefile import className. It describes commonly used Python modules like sys, os, and math. It also covers defining your own modules, directories for module files, object-oriented programming in Python including defining classes, creating and deleting instances, methods and self, accessing attributes and methods, attributes, inheritance, and redefining methods.
Python allows importing and using classes and functions defined in other files through modules. There are three main ways to import modules: import somefile imports everything and requires prefixing names with the module name, from somefile import * imports everything without prefixes, and from somefile import className imports a specific class. Modules look for files in directories listed in sys.path.
Classes define custom data types by storing shared data and methods. Instances are created using class() and initialized with __init__. Self refers to the instance inside methods. Attributes store an instance's data while class attributes are shared. Inheritance allows subclasses to extend and redefine parent class features. Special built-in methods control class behaviors like string representation or iteration.
Here is a Python class with the specifications provided in the question:
class PICTURE:
def __init__(self, pno, category, location):
self.pno = pno
self.category = category
self.location = location
def FixLocation(self, new_location):
self.location = new_location
This defines a PICTURE class with three instance attributes - pno, category and location as specified in the question. It also defines a FixLocation method to assign a new location as required.
This document provides an overview of object-oriented programming (OOP) with Python. It defines some key OOP concepts like objects, classes, encapsulation, inheritance, and polymorphism. It explains that in OOP, data and functions that operate on that data are bundled together into objects. Classes provide templates for creating objects with common properties and functions. The document also gives examples of various OOP features like class variables, instance variables, methods, and constructors.
Class, object and inheritance in pythonSantosh Verma
The document discusses object-oriented programming concepts in Python, including classes, objects, methods, inheritance, and the built-in __init__ method. Classes are created using the class keyword and contain attributes and methods. Methods must have a self parameter, which refers to the instance of the class. The __init__ method is similar to a constructor and is called when an object is instantiated. Inheritance allows one class to inherit attributes and methods from another class.
Chap 3 Python Object Oriented Programming - Copy.pptmuneshwarbisen1
The document discusses object oriented programming concepts in Python including classes, objects, instances, methods, inheritance, and class attributes. It provides examples of defining classes, instantiating objects, using methods, and the difference between class and instance attributes. Key concepts covered include defining classes with the class keyword, creating object instances, using the __init__() method for initialization, and allowing derived classes to inherit from base classes.
This document discusses object-oriented programming concepts in Python including:
- Classes define templates for objects with attributes and methods. Objects are instances of classes.
- The __init__ method initializes attributes when an object is constructed.
- Classes can make attributes private using double underscores. Encapsulation hides implementation details.
- Objects can be mutable, allowing state changes, or immutable like strings which cannot change.
- Inheritance allows subclasses to extend and modify parent class behavior through polymorphism.
This document discusses object-oriented programming concepts in Python like classes, objects, encapsulation, inheritance and polymorphism. It explains that classes are user-defined blueprints that contain data fields and methods, and objects are instances of classes. The key concepts of OOP like data encapsulation, abstraction, inheritance and polymorphism are explained with examples in Python. Various special methods like __init__(), __str__(), __repr__() and their usage with classes are also covered.
This document discusses object-oriented programming concepts in Python including classes, objects, attributes, methods, inheritance, and method overriding. It defines a MyVector class with x and y attributes and methods to add vectors and display their count. Access specifiers like private and built-in are covered. Python uses garbage collection and has no destructors. Inheritance allows a SubVector class to extend MyVector, and a method can be overridden to change a class's behavior.
This document provides an introduction to object oriented programming in Python. It discusses why OOP is useful, defines some key concepts like classes, objects, methods, and variables. It provides an example of modeling a Taxi using a Taxi class with attributes like driver name and methods like pickUpPassenger. It shows how to define a class, create objects from the class, and call methods on those objects. It also introduces the concept of class variables that are shared among all objects versus instance variables that are unique to each object.
در این جلسه به بررسی بحث برنامه نویسی شی گرا و کلاس ها در پایتون پرداختیم
PySec101 Fall 2013 J7E1 By Mohammad Reza Kamalifard
Talk About:
Object oriented programming and Classes in Python
This document discusses Python modules, classes, inheritance, and properties. Some key points:
- Modules allow the organization of Python code into reusable libraries by saving code in files with a .py extension. Modules can contain functions, variables, and be imported into other code.
- Classes are templates that define the properties and methods common to all objects of a certain kind. The __init__() method initializes new objects. Inheritance allows child classes to inherit properties and methods from parent classes.
- Properties provide a way to control access to class attributes, allowing them to be accessed like attributes while hiding the implementation details behind getter and setter methods.
Object-oriented programming (OOP) organizes code around data objects rather than functions. In Python, classes are user-defined templates for objects that contain attributes (data) and methods (functions). When a class is instantiated, an object is created with its own copies of the attributes. Self refers to the object itself and allows methods to access and modify its attributes. Classes in Python allow for code reusability, modularity, and flexibility through encapsulation, inheritance, and polymorphism.
Python classes allow for the creation of object-oriented programming in Python. Classes define blueprints for objects with shared attributes and behaviors. Key aspects of classes include defining attributes and methods, constructing objects from classes, inheritance that allows subclasses to extend parent classes, and special methods that enable built-in behaviors. Classes are a fundamental part of Python that enable code reuse and organization.
Python classes allow for the creation of object-oriented programming through defining blueprints for objects with shared attributes and behaviors. Classes are created using the class keyword and contain attributes like variables and methods like functions. Objects are instantiated from classes and can access both class level and instance level attributes. Key concepts covered include inheritance, encapsulation, polymorphism, and special methods.
This document provides an overview of object-oriented programming (OOP) with Python. It defines some key OOP concepts like objects, classes, encapsulation, inheritance, and polymorphism. It explains that in OOP, data and functions that operate on that data are bundled together into objects. Classes provide templates for creating objects with common properties and functions. The document also gives examples of various OOP features like class variables, instance variables, methods, and constructors.
Class, object and inheritance in pythonSantosh Verma
The document discusses object-oriented programming concepts in Python, including classes, objects, methods, inheritance, and the built-in __init__ method. Classes are created using the class keyword and contain attributes and methods. Methods must have a self parameter, which refers to the instance of the class. The __init__ method is similar to a constructor and is called when an object is instantiated. Inheritance allows one class to inherit attributes and methods from another class.
Chap 3 Python Object Oriented Programming - Copy.pptmuneshwarbisen1
The document discusses object oriented programming concepts in Python including classes, objects, instances, methods, inheritance, and class attributes. It provides examples of defining classes, instantiating objects, using methods, and the difference between class and instance attributes. Key concepts covered include defining classes with the class keyword, creating object instances, using the __init__() method for initialization, and allowing derived classes to inherit from base classes.
This document discusses object-oriented programming concepts in Python including:
- Classes define templates for objects with attributes and methods. Objects are instances of classes.
- The __init__ method initializes attributes when an object is constructed.
- Classes can make attributes private using double underscores. Encapsulation hides implementation details.
- Objects can be mutable, allowing state changes, or immutable like strings which cannot change.
- Inheritance allows subclasses to extend and modify parent class behavior through polymorphism.
This document discusses object-oriented programming concepts in Python like classes, objects, encapsulation, inheritance and polymorphism. It explains that classes are user-defined blueprints that contain data fields and methods, and objects are instances of classes. The key concepts of OOP like data encapsulation, abstraction, inheritance and polymorphism are explained with examples in Python. Various special methods like __init__(), __str__(), __repr__() and their usage with classes are also covered.
This document discusses object-oriented programming concepts in Python including classes, objects, attributes, methods, inheritance, and method overriding. It defines a MyVector class with x and y attributes and methods to add vectors and display their count. Access specifiers like private and built-in are covered. Python uses garbage collection and has no destructors. Inheritance allows a SubVector class to extend MyVector, and a method can be overridden to change a class's behavior.
This document provides an introduction to object oriented programming in Python. It discusses why OOP is useful, defines some key concepts like classes, objects, methods, and variables. It provides an example of modeling a Taxi using a Taxi class with attributes like driver name and methods like pickUpPassenger. It shows how to define a class, create objects from the class, and call methods on those objects. It also introduces the concept of class variables that are shared among all objects versus instance variables that are unique to each object.
در این جلسه به بررسی بحث برنامه نویسی شی گرا و کلاس ها در پایتون پرداختیم
PySec101 Fall 2013 J7E1 By Mohammad Reza Kamalifard
Talk About:
Object oriented programming and Classes in Python
This document discusses Python modules, classes, inheritance, and properties. Some key points:
- Modules allow the organization of Python code into reusable libraries by saving code in files with a .py extension. Modules can contain functions, variables, and be imported into other code.
- Classes are templates that define the properties and methods common to all objects of a certain kind. The __init__() method initializes new objects. Inheritance allows child classes to inherit properties and methods from parent classes.
- Properties provide a way to control access to class attributes, allowing them to be accessed like attributes while hiding the implementation details behind getter and setter methods.
Object-oriented programming (OOP) organizes code around data objects rather than functions. In Python, classes are user-defined templates for objects that contain attributes (data) and methods (functions). When a class is instantiated, an object is created with its own copies of the attributes. Self refers to the object itself and allows methods to access and modify its attributes. Classes in Python allow for code reusability, modularity, and flexibility through encapsulation, inheritance, and polymorphism.
Python classes allow for the creation of object-oriented programming in Python. Classes define blueprints for objects with shared attributes and behaviors. Key aspects of classes include defining attributes and methods, constructing objects from classes, inheritance that allows subclasses to extend parent classes, and special methods that enable built-in behaviors. Classes are a fundamental part of Python that enable code reuse and organization.
Python classes allow for the creation of object-oriented programming through defining blueprints for objects with shared attributes and behaviors. Classes are created using the class keyword and contain attributes like variables and methods like functions. Objects are instantiated from classes and can access both class level and instance level attributes. Key concepts covered include inheritance, encapsulation, polymorphism, and special methods.
Creating Python Variables using Replit softwareafsheenfaiq2
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Strings in Python are arrays of bytes representing Unicode characters. Individual characters are represented as strings of length 1. Strings are immutable, so their elements cannot be modified once created. However, strings can be sliced to access substrings.
Python has many built-in string methods for common string operations like capitalization, stripping whitespace, formatting, searching/replacing substrings and more. Methods like find(), count(), startswith() check for substrings within a string. Length, case changing, and padding methods modify strings. Character methods like ord() and chr() convert between characters and ASCII values.
This document provides instructions for a lesson on using the Size block in Scratch to create animations showing growing and shrinking effects. The lesson objective is for students to design and create an animation using the Size block to change a sprite's size. The success criteria are that students should be able to make a sprite grow and shrink in size and repeat the motion. Students are instructed to choose a backdrop and two sprites, then use the Size block to show a growing and shrinking effect and submit a screenshot.
This document provides an overview of using lists and dictionaries in Python. It discusses how to create, modify, and access elements in lists and dictionaries. Some key points covered include using list methods like append(), sort(), and remove() to manipulate list elements, creating nested lists to group related data, and using dictionaries to store and lookup data through key-value pairs. Shared references in lists are also explained, where modifying a list through one reference variable affects other variables referring to the same list.
This document discusses the string data type in Python. It explains that strings are sequences of characters that can be indexed, sliced, concatenated, and operated on using various string methods. Lists are also introduced as mutable sequences that can contain heterogeneous data types. Common string and list operations like indexing, slicing, length calculation, and concatenation are demonstrated through examples.
Gr 12 - Buzzer Project on Sound Production (W10).pptxafsheenfaiq2
This document provides instructions for a lesson on buzzer sensors for an Arduino project. It includes:
1) Objectives to define and explain the construction and working of active and passive buzzer sensors, and create a project using them.
2) A list of materials needed for the sound production project, including an Arduino UNO board, sensor shield, passive buzzer, and jumper wires.
3) Directions to connect the components, upload code to produce sounds with the passive buzzer, and compare it to an active buzzer.
This document discusses various network topologies including bus, ring, star, mesh, and hybrid topologies. It describes the basic characteristics of each topology such as their physical layout, advantages, and disadvantages. A bus topology uses a single backbone cable to connect all nodes without devices, while a ring topology connects each node to the two nearest in a circular formation. A star topology connects all nodes to a central hub or switch. A mesh topology fully connects all nodes to each other. Choosing a topology depends on factors like the network size, expected growth, and need for fault tolerance.
The document provides an overview of an Internet-of-Things course, including weekly topics, labs, and administrative items. The course covers fundamentals of IoT in the first week, then moves to topics like human-computer interfaces, computer networks, sensor networks, IoT cloud/analytics, and security. Labs involve programming sensors, networks, and IoT integration. Administrative items include assignments, exams, and weekly lab reports.
This document provides an overview of Python programming concepts for a summer engineering program. It covers setting up Python environments, basic syntax like indentation and variable types, arithmetic and logical operators, conditional statements like if/else and for/while loops, functions, error handling, file input/output, and two assignment tasks involving computing prices from stock and writing/reading to a file.
This document provides information about a Scratch programming course, including lesson plans, objectives, and instructions. It summarizes that students should maintain a notebook for the Scratch course with dates, topics, standards and objectives for each lesson. It also describes creating accounts on the Scratch website to work on projects and share them in the classroom. The first chapter covers differentiating between programs and programming, and using blocks like motion to make a sprite move on the screen.
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Looking for an honest take on Soulmaite? This Soulmaite review covers everything you need to know—from features and pricing to how well it performs as a real AI soulmate. We share how users interact with adult chat features, AI girlfriend 18+ options, and nude AI chat experiences. Whether you're curious about AI roleplay porn or free AI NSFW chat with no sign-up, this review breaks it down clearly and informatively.
Discover 7 best practices for Salesforce Data Cloud to clean, integrate, secure, and scale data for smarter decisions and improved customer experiences.
Bridging the divide: A conversation on tariffs today in the book industry - T...BookNet Canada
A collaboration-focused conversation on the recently imposed US and Canadian tariffs where speakers shared insights into the current legislative landscape, ongoing advocacy efforts, and recommended next steps. This event was presented in partnership with the Book Industry Study Group.
Link to accompanying resource: https://bnctechforum.ca/sessions/bridging-the-divide-a-conversation-on-tariffs-today-in-the-book-industry/
Presented by BookNet Canada and the Book Industry Study Group on May 29, 2025 with support from the Department of Canadian Heritage.
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Mary Meeker’s 2024 AI report highlights a seismic shift in productivity, creativity, and business value driven by generative AI. She charts the rapid adoption of tools like ChatGPT and Midjourney, likening today’s moment to the dawn of the internet. The report emphasizes AI’s impact on knowledge work, software development, and personalized services—while also cautioning about data quality, ethical use, and the human-AI partnership. In short, Meeker sees AI as a transformative force accelerating innovation and redefining how we live and work.
In this talk, Elliott explores how developers can embrace AI not as a threat, but as a collaborative partner.
We’ll examine the shift from routine coding to creative leadership, highlighting the new developer superpowers of vision, integration, and innovation.
We'll touch on security, legacy code, and the future of democratized development.
Whether you're AI-curious or already a prompt engineering, this session will help you find your rhythm in the new dance of modern development.
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2. Lecture 3 outline
• Python class and object
• Class implementation with Python
• Add attributes and methods
• Initialisation of objects
• Class vs instance variables
• Class vs instance vs static methods
• Public, protected and private variables and methods
• A case study
2
4. Class definition
To define a class you need to:
1. Use the class keyword (spelled with all lowercase letters)
2. Specify its name. A class name is its identifier.
By convention, class names
- can include only letters, digits, and underscores. No spaces.
- begin with a capital letter. If several words are combined, each shall start with a capital letter too
- should be meaningful DpGh, Abc, R1,WelcomeToPython, StaffMember, StreamBuffer
3. The class definition line is followed by the class contents, indented. pass can
be
used for skipping the class body.
4. Python uses a four-space indentation to delimit the classes, rather than
brackets
class HelloWorld:
pass
Class body
Class declaration
5. Class definition
• Although our first class does nothing, we still can run the program.
1. Save the class definition in a file named HelloWorld.py
2. Implement and run the program in IDLE.
6. Adding arbitrary attributes
• Objects should contain data which are defined as the attribute
• We can set arbitrary attributes on an instantiated object using ‘.’ (dot
notation).
• Syntax: <object>.<attribute> = <value>
7. Adding object behaviors
• We have data, and it is time to add behaviors.
• We start with a method called ‘greet’ which prints “Hello object world”.
• ‘greet’ method does not require any parameters.
• We call the method through the dot notation: <object>.<method>
8. Adding behaviors
• In Python, a method is defined with the def keyword, followed by a space,
the name of the method, and a set of parentheses containing the
parameter list.
• Method definition is terminated with a colon (:)
• The method body starts from the next line and is indented.
Syntax:
<def><methodName><(parameter list):>
<four space indentation><method body>
9. ‘self’
argument
• With the same class definition, we can create different objects.
Therefore, we need to know which object calls the methods (object
methods).
• Object methods shall contain an argument referring to the object
itself.
• Normally, this argument is named ‘self’. The ‘self’ argument is a
reference to the object that the method is being invoked on.
• Of course, you can also call it by another name, such as ‘this’ or ‘bob’.
But we never seen a real Python programmer use any other name for
this variable
• A normal function or a class method does not have this ‘self’
argument.
10. ‘self’
argument
• In Python OOP, a method is a function attached to a class.
• The ‘self’ parameter is a specific instance of that class.
• If you call the method with two different instances (objects), you are
calling the same method twice but passing two different objects as
the ‘self’ parameter
• When we call <object>.<method>, we do not have to pass the ‘self’
argument into it. It is because Python automatically pass it, i.e.,
method(object)
• Alternatively, we can invoke the function by the class name, and
explicitly pass our object as the ‘self’ argument using
<class>.<method(object)>
12. More arguments
• A method can contain multiple arguments
• Use the dot notation to call the method with all argument values (still
no need to include the ‘self’ argument) inside the parentheses
13. Adding attributes in your class definition
What if we forget to call the reset() function?
14. Summary
• Python is an interpreted language. The interpreter only ‘knows’ the code has been
executed.
• The ‘self’ argument is a reference to the object self. We should use ‘self.’ notation to access
the object functions and attribute values.
• If we try to access an attribute without a value, we will receive an error. Therefore, we must
make sure the attribute has a value before we use it.
• The ’reset()’ and ‘move()’ methods in the previous example assign values to attributes
‘self.x’ and ‘self.y’, and one of them must be executed for both point objects before we
calculate the distance of the two point objects.
• However, how do users know that? Furthermore, how do we force users to call the
‘reset()’
method?
• The better way is to let the interpreter call ‘reset()’ automatically for every new object
created.
• In OOD, a constructor (i.e., the function with the class name) refers to a special method that
creates and initialises the object automatically when it is created
• The Python initialisation method is the same as any other method but with a special name,
init (the leading and trailing are double underscores)
16. Explain your class
• It is important to write API documentation to summarize what each object and
method does
• The best way to do it is to write it right into your code through the docstrings
• Docstrings are simply Python strings enclosed with apostrophes (') or quotation
marks (") characters.
• If docstrings are quite long and span multiple lines (the style guide suggests that
the line length should not exceed 80 characters), it can be formatted as multi-line
strings, enclosed in matching triple apostrophe (''') or triple quote (""") characters.
• A docstring should clearly and concisely summarize the purpose of the class or
method it is describing.
• It should explain any parameters whose usage is not immediately obvious and is
also a good place to include short examples of how to use the API.
• Any caveats or problems an unsuspecting user of the API should be aware of
should also be noted.
18. Object (instance) vs class (static) variables
• Object variables are for data unique to
each object.
• Object variables are defined inside
methods with the prefix ‘self’
• Access via self.<InstanceVariable>
• Class variables are for data shared by all
objects of the same class.
• Class variables are defined outside
methods
• Access via cls.<ClassVariable> or
<ClassName>.<ClassVariable>
19. Instance (object) vs class (static) variables
• start_point_x and start_point_y are class variables
• Changing the class variable values with Object point1,
then we can see the class variable values are modified
with Object point2
• Object point1 changes the start point from (0, 0) to
(1, 1). However, Object point2 is not initialised by the
new start point (1,1). Can you guess why?
• Can we use Point.start_point_x and
Point_start_point_y in the init() method?
20. Instance (object) vs class (static) variables
• No, we can not. It is because the class variables are not
created yet when we call the init() method
• How to resolve this problem?
• We use a sentinel default value instead.
21. Sentinel Default Value
• Can you understand and explain how the code is
executed and what the results are?
• Try to ‘run’ the code in your mind and write
down all outputs.
22. Class method
• Problem: we still have to create a Point object first, and then we can
modify the class variable start_point_x and start_point_y.
• Question: can we modify the start point directly without creating a Point
object?
• Answer: yes, we can. We can define a ‘change_start_point()’ method as
a class method by marking this method with a ‘@classmethod’
decorator.
• Then we can call the method with the class name, i.e.,
<ClassName>.<ClassMethod>.
• Actually, you can also call the class method with an object of the class,
such as <objectName>.<ClassMethod>. They do the same job.
23. Class method vs object method
• The object method has access to the object via the
’self’ argument. When the method is called, Python
replaces the ’self’ argument with the real object
name.
• Calling class method doesn’t have access to the
object, but only to the class. Python automatically
passes the class name as the first argument to the
function when we call the class method.
• Summary: Python calls the object method by
passing the object name as the first argument, and
calls the class method by passing the class name as
the first argument
24. Static method
• Question: Java has the static method, does Python also have the
static method?
• Answer: Yes, Python also has the static method, but the
definition of
‘static’ in Python is very different from Java or other OOPs.
• Java’s static method is the same as Python’s class method
• Python’s static method is the same as Python’s normal method,
i.e.,
no object instance or class will be pasted as the first argument.
• Python’s static method can be defined by marking this method with a
‘@staticmethod’ decorator.
• You are allowed to call a static method via either
26. Python access control
Most OOP languages have a concept of access control.
• (+) public members are accessible from outside the class.
• (-) private members are accessible from inside the class only.
• (#) protected members are accessible from inside the class or sub-classes
However, Python does not follow this exactly.
• Python does not believe in enforcing laws that might someday get in your way.
• Technically, all class members (attributes and methods) are publicly available, i.e., they can be
accessed directly from external.
• In Python, prefixes are used to only interpret the access control of members.
• _ (single underscore) prefixed to a member makes it protected but still can be accessed directly.
• (double underscore) prefixed to a member makes it private. It gives a strong suggestion not to
touch it from outside the class. Any attempt to do so will result in an AttributeError.
• However, Python performs name mangling of private variables. Every private member with a
double underscore can be accessed by adding the prefix ‘_<ClassName>’. So, private members can
still be accessed from outside the class, but the practice should be refrained.
28. Python execution control
• A program written in C or Java needs the main() function to indicate the
starting point of execution.
• Python does not need the main() function as it is an interpreter-based
language.
• The execution of the Python program file starts from the first
statement.
• Python uses a special variable called ‘ name ’ (string) to
maintain the
scope of the code being executed.
• The top-level scope (top-level code executes here) is referred by the
value
‘ main ’
• You can check the scope in Python shell by typing ‘ name ’ in
IDEL.
29. Python execution control
• When you execute functions and
modules in the interpreter
shell directly,
they will be executed in the top-
level scope ‘ main ’
• We can also save a Python
program as a Python file, which
may contain multiple functions
and statements, such as
30. Python execution control
• We can use the command prompt/terminal to execute the Python file as a script. Then
the scope is ‘ main ’.
• We can also use the Python file as a module in another file or in interactive shell by
importing it. Then the scope is the module’s name, but not the ‘ main ’.
31. Python execution control
• The import statement starts
executing from the first statement
till the last statement.
• What if we just want to use the
‘add()’ method but not print the
details?
• We can use the special variable
‘ name ’ to check the scope
and execute the other statements
only when it executes from the
command prompt/terminal with
the scope of ‘ main ’ but not
when importing.
32. Python execution control
• However, when we execute it
from the command
prompt/terminal, it still executes
all statements because of it
being executed in the top-level
scope
‘ main ’.
• Thus, value of the ‘ name ’
allows the Python interpreter to
determine whether a module is
intended to be an executable
script.
33. A case study
Design and implement a Python program with OOD & OOP to calculate the
length of a given line segment.
Step 1: OOA
• To calculate the length of a given line segment, a LineSegment class can be
defined. The LineSegment class should contain two points, i.e., the starting
point and the ending point. The length of a line segment is the Cartesian
distance between the two points. So we also need to define a Point class.
• So the LineSegment class should have two points (attribute) and can
calculate the Cartesian distance of two points (behavior)
• To represent a point, a Point class should contain the coordinate (x, y) as its
attributes.
34. A case study
Design and implement a Python program with OOD & OOP to calculate the
length of a given line segment.
Step 2: OOD (UML)
𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒 = (𝑥1 − 𝑥2)2+(𝑦1
− 𝑦2)2
35. A case study
Design and implement a Python program with
OOD & OOP to calculate the length of a given
line segment.
Step 3: OOP (Python): complete the Python
class code and test code. Remember, you should
create the ‘ init ’ method for every class.
Step 4 Execution Control: use the ‘ name ’
variable to ensure your testing code is only
executed in the command prompt/terminal.
A further question: can you modify this design
and code to calculate the total length of
consecutive line segments, such as
(0,0)->(3,4)->(5,7)->(2,8)?
