MCA S1 Python U1 - Introduction to Python.pdf

Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 An Int...

Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 An Introduction to Python Programming What is Python Programming? Python is a widely used, popular, general-purpose programming language that is interpreted, interactive, object-oriented, and high-level. It was designed by Guido van Rossum in 1991 and is maintained by the Python Software Foundation. Python emphasizes code readability and has a clean syntax that allows programmers to write fewer lines of code compared to other programming languages. Python is known for its ability to help developers work quickly and efficiently, integrating systems with minimal effort. Characteristics of Python 1. Interpreted: Python code is processed at runtime by the interpreter. There is no need for compiling the program before execution, unlike languages such as C or C++. This is similar to languages like Perl and PHP. 2. Interactive: Python provides an interactive mode where programmers can write and execute code line-by-line using the Python prompt. This feature allows for quick testing and debugging. 3. Object-Oriented: Python supports object-oriented programming (OOP), which organizes code around objects (data) and methods (functions) that operate on the objects. This style encapsulates code within reusable and maintainable objects. 4. Beginner-Friendly: Python is often recommended as the first language for beginners because of its simple and clean syntax. It allows developers to create a wide range of applications, from text processing to web browsers and games. Python Versions There are two major versions of Python: Python 2: Released on October 16, 2000, with many features that contributed to Python’s popularity. Python 3: Released on December 3, 2008, it introduced new features and was designed to address shortcomings in Python 2. Python 3 is now the standard, and Python 2 has officially reached the end of its life. Asst. Prof. Mitul Ghediya Page | 1  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Why Use Python? Python has a variety of characteristics that make it an ideal language for many use cases: 1. Open Source: Python is free to use and distribute, even for commercial purposes. 2. Easy to Learn: Python’s simple syntax and readability make it a perfect language for beginners. 3. Versatile: Python is a multi-purpose language that can be used for web development, data analysis, machine learning, automation, and much more. 4. Extensive Libraries: Python comes with powerful built-in libraries for various tasks such as artificial intelligence (AI), machine learning (ML), and data visualization. 5. In Demand: Python developers are in high demand, and the language often ensures high salaries due to its popularity in various industries. 6. Supports Multiple Paradigms: Python supports both structured programming (procedural programming) and object-oriented programming (OOP). 7. Dynamic Typing: Python allows variables to change types dynamically without explicitly declaring their types. 8. Automatic Memory Management: Python includes automatic garbage collection, freeing up memory that is no longer needed. 9. Platform-Independent: Python programs can run on various platforms, such as Windows, macOS, Linux, etc., as long as the system has a Python interpreter. How to Start with Python 1) Finding an Interpreter Before you start writing Python code, you need an interpreter to execute your programs. There are several online interpreters available to start with Python without any installation: GeeksforGeeks IDE: https://ide.geeksforgeeks.org/ Ideone: http://ideone.com/ CodePad: http://codepad.org/ Python Installation on Different Platforms: Windows: Python can be installed from the official site: https://www.python.org/downloads/. After installation, you can use IDLE (Integrated Development and Learning Environment) to run Python scripts. Linux: Most Linux distributions like Ubuntu and Fedora come with Python pre- installed. You can check the Python version by typing python or python3 in the terminal. macOS: Python 2.7 comes pre-installed with macOS, but you may need to install Python 3 manually from https://www.python.org/. Asst. Prof. Mitul Ghediya Page | 2  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 2) Writing Your First Python Program To start programming in Python, you can write your first script with the following steps: Example: print("Hello, Python!") Line 1: This is the print function, which outputs text to the console. It prints Hello, Python!. 3) Prerequisites for Learning Python A background in programming is helpful but not necessary. Python is a great language for those new to programming. Differences Between Scripting Languages and Programming Languages Scripting Languages: Python can be used as a scripting language where code is written to automate tasks and interpreted directly without compiling. Programming Languages: Python can also be used as a general-purpose programming language to build larger applications like games, web servers, etc. Why Use Python? Python is widely used due to several features that make it both powerful and easy to use: 1. Object-Oriented: Python supports key OOP concepts such as polymorphism, overloading, and inheritance, making it suitable for building complex applications. 2. Indentation: Unlike many other programming languages, Python uses indentation to define code blocks. This improves readability and enforces clean coding practices. 3. Free and Open Source: Python is available free of charge and is open-source, meaning anyone can contribute to its development. 4. Powerful Libraries: Python comes with many built-in libraries for tasks like data processing, web development, and scientific computing. 5. Portability: Python runs on virtually all major platforms (Windows, macOS, Linux) without requiring any modifications to the code. 6. Easy to Use and Learn: Python is known for its simplicity, which allows beginners to quickly grasp programming concepts. 7. Interpreted Language: Python is interpreted, meaning that each line of code is executed as it is written, making it easy to debug and test code. 8. Interactive Language: Python allows developers to interact directly with the interpreter for quick prototyping and testing. Asst. Prof. Mitul Ghediya Page | 3  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 9. Straightforward Syntax: Python’s syntax is clean and straightforward, making it easy to learn, read, and write code. Conclusion Python is a versatile and powerful programming language that is easy to learn for beginners but also suitable for building complex systems. Its wide array of libraries, portability, and dynamic nature make it one of the most popular programming languages today, used in industries ranging from web development to data science and artificial intelligence. Asst. Prof. Mitul Ghediya Page | 4  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Key Features of Python Python is known for several features that make it one of the most popular and versatile programming languages. Below is a detailed explanation of Python's core features: 1. Easy to Learn Simple Structure: Python has a clean and easy-to-understand syntax, which reduces the learning curve, especially for beginners. Few Keywords: Python’s simplicity comes from its limited number of keywords and commands, making it easier to write and learn. Clear Syntax: The structure of Python code is straightforward, allowing new programmers to focus on problem-solving rather than the complexities of the language. 2. Readable Well-Structured Code: Python code is easily readable and uses indentation instead of braces {} or other symbols to define blocks of code. Visual Clarity: Python programs are clean and readable, which makes them easy to maintain and modify. 3. Maintainable Consistent Syntax: Python’s uniform and straightforward syntax means that it’s easier to maintain, update, and improve existing codebases. Manageable Source Code: The simplicity and readability of Python make managing large projects more efficient. 4. Broad Standard Library Extensive Libraries: Python comes with a comprehensive set of libraries that handle various tasks like file I/O, system calls, web development, and more. Cross-Platform Compatibility: Python’s libraries work on multiple platforms like UNIX, Windows, and macOS, ensuring consistent behavior across systems. Asst. Prof. Mitul Ghediya Page | 5  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 5. Interactive Mode Real-Time Testing: Python supports an interactive mode where developers can type commands directly into the interpreter and see results immediately. This allows for quick testing and debugging. Immediate Feedback: The interactive shell provides instant feedback, making it easier to experiment with code and debug problems in real-time. 6. Portable Cross-Platform Compatibility: Python runs seamlessly across multiple hardware platforms and operating systems (Linux, Windows, macOS, Solaris, etc.), providing a consistent environment regardless of where it is executed. 7. Extendable Add Custom Modules: Python can integrate with C and C++ code to extend the language and add custom low-level modules. Efficient Tool Customization: Developers can extend Python’s functionality by incorporating custom tools and modules into the interpreter. 8. Database Support Commercial Databases: Python provides interfaces for working with most major commercial databases, making it an excellent choice for applications requiring database integration. 9. GUI Programming Graphical User Interface (GUI): Python supports multiple libraries (e.g., Tkinter, PyQt, and wxPython) for creating GUI applications that can run on different systems like Windows, macOS, and UNIX. 10. Scalable Asst. Prof. Mitul Ghediya Page | 6  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Large-Scale Programs: Python provides excellent support for building large-scale applications with well-organized structure and maintainability. It’s more scalable than shell scripting languages. 11. Platform Independent Cross-Platform Execution: Python programs can run on various operating systems (Linux, Windows, macOS) without modification, as long as a compatible Python interpreter is installed. 12. Free and Open Source No Cost: Python is free to use, distribute, and modify, even for commercial purposes. Open Source: Python’s source code is publicly available and anyone can contribute to its development or make modifications. 13. High-Level Language Abstracts Low-Level Details: Python handles many of the complexities of low-level programming, such as memory management and system interactions, allowing developers to focus on the application’s logic. 14. Simple and Closer to English User-Friendly Syntax: Python’s syntax is designed to be simple and intuitive, often resembling plain English, making it easier to understand the code. Problem-Solving Focus: Python emphasizes solving problems over dealing with complicated syntax, making it an excellent choice for developers focusing on quick and efficient solutions. 15. Embeddable Integrate with Other Languages: Python can be embedded in other programming languages, such as C/C++, to provide scripting capabilities to those applications. Asst. Prof. Mitul Ghediya Page | 7  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 16. Robust Memory Management: Python has automatic memory management with a built-in garbage collector that helps in cleaning up unused objects. Exception Handling: Python has strong support for exception handling, allowing developers to manage errors gracefully and ensure smoother execution of programs. Conclusion: Python's features make it a powerful, versatile, and user-friendly language that is ideal for a wide range of applications, from web development to data science, machine learning, and automation. Its simplicity and readability, combined with its powerful libraries and cross- platform support, make Python a top choice for developers at all levels. Asst. Prof. Mitul Ghediya Page | 8  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Applications of Python Python is a versatile programming language used in various domains due to its simplicity, large standard library, and powerful frameworks. Below are some common applications of Python: 1. Web Applications: Python is widely used for web development, offering several powerful frameworks and libraries that make creating web apps easier. Popular Libraries/Frameworks: o Django and Pyramid: For large-scale web applications (e.g., Instagram). o Flask and Bottle: Lightweight frameworks suited for small projects or microservices. o Plone and Django CMS: Used for building content management systems (CMS). Example Use Case: Instagram is powered by Django, showcasing Python’s capability to handle large- scale applications with millions of users. Asst. Prof. Mitul Ghediya Page | 9  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 2. Desktop GUI Applications: Python supports building desktop applications with graphical user interfaces (GUIs). Popular Libraries/Frameworks: o Tkinter: A built-in Python library for basic GUI applications. o wxPython: A more advanced GUI toolkit for building native applications. o Kivy: A library for building multitouch apps. o PyQt or PySide: For building sophisticated and professional-grade GUIs. Example Use Case: Spotify desktop app uses Python for some of its backend services. 3. Console-Based Applications: Python can be used to create applications that run in a terminal or command-line environment. REPL (Read-Eval-Print Loop): Python’s interactive shell is perfect for building console applications. Libraries: Python’s built-in libraries like argparse and cmd make it easier to parse input and manage arguments. Example Use Case: Command-line tools like Tox for testing Python projects use Python for building, managing dependencies, and testing. 4. Software Development Tools: Python is extensively used in the development of software tools, for build automation, testing, and project management. Popular Libraries/Frameworks: o SCons: A tool for build control. o Buildbot and Apache Gump: Used for automated testing and continuous integration. o Roundup and Trac: For project management and bug tracking. Example Use Case: Asst. Prof. Mitul Ghediya Page | 10  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 SCons is used for build automation and is written entirely in Python. 5. Scientific and Numeric Applications: Python plays a key role in scientific computing and data analysis. It has become the go-to language in fields such as data science, artificial intelligence (AI), and machine learning (ML). Popular Libraries/Frameworks: o NumPy, Pandas, SciPy: Libraries used for data analysis, manipulation, and numerical calculations. o Scikit-learn: A machine learning library that provides algorithms for classification, regression, and clustering. o Matplotlib: For data visualization through graphs, charts, and plots. Example Use Case: Python is used in machine learning models for data processing, model training, and analysis. 6. Business Applications: Python is used to create enterprise-level business applications such as ERP systems and e- commerce platforms. Popular Tools: o Odoo: A suite of open-source business apps. o Tryton: A platform for business applications. Example Use Case: Odoo is widely used for business management, including CRM, e-commerce, and project management. 7. Audio/Video Applications: Python is capable of building multimedia applications that can process, play, and edit audio and video content. Popular Libraries/Frameworks: Asst. Prof. Mitul Ghediya Page | 11  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 o GStreamer: For multimedia framework support. o Pyglet: A cross-platform windowing and multimedia library. o Qt Phonon: For handling multimedia within the Qt framework. Example Use Case: Python can be used to develop video editing tools or streaming applications. 8. 3D CAD Applications: Python is also used in engineering and architecture for designing 3D models. Popular Libraries/Tools: o Fandango o HeeksCNC o AnyCAD Example Use Case: Python is employed in CAD software for 3D modeling and engineering design processes. 9. Enterprise Applications: Python is highly suitable for creating large-scale applications used within enterprises. Popular Tools: o OpenERP: An open-source suite of business applications. o Tryton: A high-level business application platform. o Picalo: For data analysis and modeling. Example Use Case: Python can be used to build enterprise resource planning (ERP) systems that integrate different business functions. 10. Image Processing Applications: Python provides libraries that allow developers to manipulate images and perform advanced image processing. Asst. Prof. Mitul Ghediya Page | 12  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Popular Libraries/Frameworks: o OpenCV: An open-source computer vision library. o Pillow: The Python Imaging Library (PIL) fork, used for basic image processing. o SimpleITK: For image segmentation and registration. Example Use Case: OpenCV is widely used for facial recognition and object detection in computer vision tasks. Conclusion: Python’s wide range of applications demonstrates its flexibility and power. From web development to data science and machine learning, Python is a crucial tool in many industries, making it a top choice for both beginners and professionals. With a large number of frameworks and libraries, Python provides efficient solutions for nearly every programming challenge. Asst. Prof. Mitul Ghediya Page | 13  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Installing Python on Windows Python is a free, open-source programming language that can easily be installed on Windows, Linux, and macOS. Here, we will focus on the process of installing Python on a Windows machine and verifying the installation. Steps to Install Python on Windows: 1. Download Python: o Go to the official Python website: https://www.python.org/downloads/. o On this page, you will find the latest version of Python for Windows. o Click the Download Python button to get the installer. 2. Run the Installer: o Once the installer is downloaded, double-click the file to run it. o During installation, check the box that says "Add Python to PATH". This step is important because it allows you to run Python from any directory in the Command Prompt. 3. Choose Installation Type: o Install Now: This option installs Python with default settings. o Customize Installation: This option allows you to select additional features, such as installing pip (Python's package manager) and configuring environment variables. 4. Installation Process: o After selecting the installation options, click the Install button. Python will begin installing on your system. o Wait for the installation to complete. Once finished, you will see a setup success screen. Verifying Python Installation: After installation, you need to verify that Python was installed correctly. Follow these steps: 1. Open Command Prompt: o Click the Start button and type cmd in the search bar to open the Command Prompt. 2. Check Python Version: o In the Command Prompt, type the following command and press Enter: python --version o If Python is installed successfully, it will display the version of Python installed on your system, like: Python 3.x.x Asst. Prof. Mitul Ghediya Page | 14  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 o If Python is not installed or added to PATH correctly, you will get an error message saying 'python' is not recognized as an internal or external command, operable program, or batch file. Opening IDLE (Python's Integrated Development and Learning Environment): Once Python is installed, you can start writing and running Python programs using IDLE, the default Python IDE. 1. Opening IDLE: o Go to the Start Menu and type IDLE. o Click on the IDLE (Python 3.x) icon to open the Python shell. o You will now be able to start writing Python code directly in the shell. Running Your First Python Program: 1. Using Command Prompt: o You can run Python directly in the Command Prompt by typing: python o This opens the Python interactive shell where you can type Python commands directly. Example: >>> print("Hello, World!") Hello, World! 2. Writing Python Scripts: o To run Python scripts, create a file with a.py extension, for example, MyScript.py, and write your Python code in it. o To execute the script, open the Command Prompt, navigate to the file location, and type: python MyScript.py Python Installation on Other Operating Systems Asst. Prof. Mitul Ghediya Page | 15  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 macOS: Python 2.7 comes pre-installed with macOS, but it's recommended to install Python 3. To install Python 3, download the installer from python.org and follow the installation instructions. You can check if Python is already installed on macOS by opening the terminal and typing: python --version Linux (Ubuntu): Python is pre-installed on most Linux distributions. For Ubuntu, you can install Python 3 using: sudo apt-get update sudo apt-get install python3 Working with Python - Code Execution Python provides two primary modes for running code: 1. Interactive Mode: o This mode allows you to enter Python commands directly into the interpreter and see the results immediately. o This is ideal for testing small pieces of code or quick experiments. Example: >>> print("Hello, World!") Hello, World! 2. Script Mode: o In script mode, you write Python code in a file with a.py extension, and then run the file using the Python interpreter. o To execute a Python script from the command line, type: python MyScript.py Conclusion: Installing Python on Windows is a straightforward process that requires downloading the installer from the Python website and running it. After installation, you can verify the setup using the Command Prompt and start writing Python code using IDLE or any text editor. With Python installed, you're ready to create scripts, web applications, or scientific projects. Asst. Prof. Mitul Ghediya Page | 16  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Python Basic Constructs Python Basic Constructs are the foundational elements that form the building blocks of any Python program. These constructs include variables, data types, operators, control structures, and more. Let’s explore them: 1. Variables and Data Types Variables: Used to store data values. A variable in Python is created when you assign a value to it. Example: x = 10 # integer name = "Python" # string pi = 3.14 # float Data Types: Python supports multiple built-in data types including: o Integers (int): Whole numbers like 10, 50, -100. o Floats (float): Decimal numbers like 3.14, -10.5. o Strings (str): A sequence of characters like "Hello, World!". o Booleans (bool): Logical values: True or False. o Lists: Ordered, mutable collections like [1, 2, 3]. o Dictionaries: Key-value pairs like {"name": "John", "age": 25}. 2. Keywords and Identifiers Keywords: Reserved words that have predefined meanings in Python. These cannot be used as variable names or identifiers. o Examples: if, else, while, for, return, def, etc. Identifiers: Names used to identify variables, functions, classes, etc. They must start with a letter or underscore (_), followed by letters, digits, or underscores. Example: my_var = 10 def my_function(): pass 3. Comments Asst. Prof. Mitul Ghediya Page | 17  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Single-line comments: Comments are used to add explanations or notes to the code and are ignored by the Python interpreter. Single-line comments start with a #. Example: # This is a single-line comment x = 10 # variable to store the value 10 Multi-line comments: For comments that span multiple lines, use triple quotes (''' or """). Example: ''' This is a multi-line comment explaining the next section of the code. ''' 4. Operators Python supports various types of operators to perform different operations on variables and data: Arithmetic Operators: Perform mathematical operations. o Example: +, -, *, /, %, ** (exponent), // (floor division) x = 10 + 5 # Addition Comparison Operators: Compare two values. o Example: ==, !=, >, =, 10: print("x is greater than 10") Python First Program Let's now write our first Python program to print a message: Writing Your First Python Program Script Begins: A Python script starts with code statements or comments. Example of First Python Program: # This is my first Python program print("Hello, Python!") Explanation: o Line 1: This is a comment. It explains that this is your first Python program. o Line 2: The print() function is used to display the message "Hello, Python!" on the console. Output: Hello, Python! Understanding Indentation in Python In Python, indentation is used to define blocks of code within control structures like functions, loops, and conditions. Without proper indentation, Python code will not execute correctly and will raise an IndentationError. Asst. Prof. Mitul Ghediya Page | 19  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Example with correct indentation: x = 5 if x > 0: print("x is a positive number") # Indented block Example with incorrect indentation: x = 5 if x > 0: print("x is a positive number") # Error: Missing indentation Asst. Prof. Mitul Ghediya Page | 20  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Conclusion Python's basic constructs such as variables, data types, operators, and control structures are fundamental to writing functional code. Its reliance on indentation for code structure ensures that the code is clean, readable, and maintainable. Understanding these foundational elements is key to mastering Python programming. Asst. Prof. Mitul Ghediya Page | 21  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Python Keywords and Identifiers 1. Python Keywords Keywords in Python are reserved words that hold special significance and are used to define the language’s syntax and structure. These words cannot be used as identifiers (names for variables, functions, classes, etc.) because they have predefined meanings within the language. As of Python 3.8, there are 35 keywords in total. Each of these serves a particular purpose in controlling the flow, defining logic, or handling exceptions in a program. List of Python Keywords: Control Flow: o if, elif, else, while, for, break, continue, return Function/Method Definition: o def, lambda Exception Handling: o try, except, finally, raise Class Definition: o class Boolean Values: o True, False, None Logical Operators: o and, or, not, is, in Others: o global, nonlocal, pass, with, async, await, yield, assert, from, import, as, del Example: if True: print("This is a keyword example") In the example above, if, True, and print are all keywords with specific uses. if is used for conditional statements, True represents a boolean value, and print is a built-in function. 2. Python Identifiers Asst. Prof. Mitul Ghediya Page | 22  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Identifiers are names used to identify variables, functions, classes, modules, or other objects in Python. They are user-defined names but must adhere to specific rules. Properly naming identifiers makes code easier to read and maintain. Rules for Identifiers: Must start with a letter: (a-z, A-Z) or an underscore (_). Followed by letters: (a-z, A-Z), digits (0-9), or underscore (_). Case-sensitive: MyVar and myvar are different identifiers. No special characters: Identifiers cannot include special symbols such as @, #, $, %, etc. Cannot use reserved keywords: Keywords like if, class, return cannot be used as identifiers. Valid Identifiers: Examples: myVariable = 10 _temp = 5 student1 = "Alice" Invalid Identifiers: Starting with a digit: o 1variable is invalid. Using special characters: o my$var is invalid. Using reserved keywords: o def = 10 is invalid because def is a reserved keyword. Example: name = "John" # 'name' is a valid identifier class_ = "Student" # 'class_' is a valid identifier (not using the reserved keyword 'class') In the example above, name is a valid identifier, as it starts with a letter and consists only of letters. class_ is also valid because the trailing underscore prevents it from conflicting with the reserved keyword class. Summary of Key Points: Keywords: Reserved words in Python with specific meanings that cannot be used as variable names. For example, if, else, class, def, etc. Identifiers: User-defined names for variables, functions, and classes. They must follow specific rules (e.g., no special characters, cannot start with a number). Asst. Prof. Mitul Ghediya Page | 23  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Understanding and following the rules for keywords and identifiers is essential for writing clean, readable, and error-free Python programs. Asst. Prof. Mitul Ghediya Page | 24  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Datatypes in Python In Python, data types are classes, and variables are instances (objects) of these classes. Because Python is a dynamically typed language, the type of a variable is determined automatically at runtime based on the value assigned to it. Different types of data require different storage methods and operations, so Python provides a wide range of built-in data types. 1. Numeric Data Types Python provides three main types of numeric data: int, float, and complex. Integers (int): o Integers are whole numbers (positive or negative) without fractions or decimal points. o Python has no limit on the size of integers. o Example: x = 10 print(type(x)) # Output: Floats (float): o Floating-point numbers are real numbers with a decimal point or in scientific notation. o Example: y = 3.14 z = 1.2e3 # Scientific notation, equivalent to 1.2 * 10^3 print(type(y)) # Output: print(type(z)) # Output: Complex Numbers (complex): o Complex numbers are written as x + yj, where x is the real part and y is the imaginary part. o Example: c = 2 + 3j print(type(c)) # Output: 2. Sequence Data Types Python supports several sequence data types, which allow the storage of multiple values in an ordered collection. These include strings, lists, and tuples. Asst. Prof. Mitul Ghediya Page | 25  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Strings (str): o Strings are sequences of characters enclosed in single, double, or triple quotes. o Example: s = "Hello, World!" print(type(s)) # Output: Lists (list): o Lists are mutable (changeable) ordered collections that can hold items of different data types. o Lists are created using square brackets []. o Example: lst = [1, 2, 3, "apple", 3.14] print(type(lst)) # Output: Tuples (tuple): o Tuples are immutable (unchangeable) ordered collections, created using parentheses (). o Example: tup = (1, 2, 3, "banana") print(type(tup)) # Output: 3. Boolean Data Type Booleans (bool): o Boolean data types have two possible values: True and False (with capital 'T' and 'F'). o Booleans are often used in conditional statements and logic operations. o Example: a = True b = False print(type(a)) # Output: Non-Boolean objects can also be evaluated in a Boolean context using functions like bool(). For example, an empty list evaluates to False, while a non-empty list evaluates to True. 4. Other Important Data Types Dictionaries (dict): o Dictionaries are collections of key-value pairs. Each key is unique, and values can be any data type. Asst. Prof. Mitul Ghediya Page | 26  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 o Example: d = {"name": "Alice", "age": 25} print(type(d)) # Output: Sets (set): o Sets are unordered collections of unique elements, created using curly braces {}. o Example: s = {1, 2, 3, 4, 4} # Duplicates are automatically removed print(type(s)) # Output: Type Conversion Python allows for type conversion between different data types using built-in functions. int(): Converts a value to an integer. o Example: int(3.14) results in 3. float(): Converts a value to a float. o Example: float(5) results in 5.0. str(): Converts a value to a string. o Example: str(25) results in "25". bool(): Converts a value to a Boolean. o Example: bool(0) results in False, while bool(1) results in True. Conclusion Python provides a wide variety of data types to handle different kinds of data, from numbers and strings to more complex collections like lists, tuples, and dictionaries. Understanding these data types and their behavior is essential for writing efficient and error-free Python programs. Asst. Prof. Mitul Ghediya Page | 27  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Python Comments In Python, comments are used to explain the code and make it more readable. Comments are ignored by the Python interpreter and do not affect the program's execution. They are useful for leaving notes for yourself or other programmers to understand the logic behind your code. 1. Purpose of Comments in Python Explain the Code: Comments help clarify what the code does, making it easier for others (or yourself) to understand the logic behind the code when revisiting it later. Increase Readability: They make the code more readable and easier to maintain by describing the purpose and functionality of code blocks. Disable Code: Comments can be used to temporarily disable a piece of code for testing purposes without deleting it. 2. Types of Comments in Python There are two main types of comments in Python: Single-line comments and Multi-line comments. 2.1 Single-Line Comments A single-line comment starts with a # symbol. Everything after the # on that line is ignored by the Python interpreter. Example: # This is a single-line comment print("Hello, World!") # This is an inline comment Explanation: o The first comment explains the print statement. o The second comment is an inline comment that appears on the same line as the code but after the code. Asst. Prof. Mitul Ghediya Page | 28  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 2.2 Multi-Line Comments Multi-line comments are used to comment on multiple lines of text. In Python, multi-line comments can be created using multiple # symbols at the beginning of each line, or by using triple quotes (""" or '''). Using # for Each Line: # This is a comment # written in # more than just one line print("Hello, World!") Using Triple Quotes: """ This is a comment written in more than just one line """ print("Hello, World!") Explanation: o In the first example, each line of the comment starts with a #. o In the second example, the triple quotes allow the creation of a block of comments. This method can also be used for documentation strings (docstrings) in functions and classes, though it technically is not intended for regular comments. 3. Comments for Documentation In Python, triple quotes are often used as docstrings to describe the functionality of a function, method, or class. These docstrings are different from regular comments because they are stored as an attribute and can be accessed using Python's help function. Example of Docstring: def my_function(): """ This function prints "Hello, World!". It demonstrates the use of docstrings. """ print("Hello, World!") Accessing Docstring: print(my_function.__doc__) Asst. Prof. Mitul Ghediya Page | 29  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 4. Advantages of Using Comments Code Clarity: Comments can clarify complex logic or calculations in your code. Collaboration: When working in teams, comments help others understand your code. Debugging: You can use comments to disable certain parts of your code during debugging without deleting them. Conclusion Comments are essential tools for writing maintainable, readable, and collaborative code in Python. Whether you use single-line or multi-line comments, they help you explain the purpose and functionality of your code clearly, making it easier for others to understand and modify it later. Asst. Prof. Mitul Ghediya Page | 30  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Python Operators In Python, operators are special symbols or keywords used to perform operations on variables and values. Python offers a wide range of operators that can be used to carry out various computations and comparisons. Python classifies operators into the following categories: 1. Arithmetic Operators Arithmetic operators are used to perform mathematical operations on numerical values. Operators: o + : Addition o - : Subtraction o * : Multiplication o / : Division o % : Modulus (remainder after division) o ** : Exponentiation (power) o // : Floor Division (rounds down the result of division) Example: x = 10 y = 3 print(x + y) # Output: 13 print(x - y) # Output: 7 print(x * y) # Output: 30 print(x / y) # Output: 3.333... print(x % y) # Output: 1 print(x ** y) # Output: 1000 (10 raised to the power of 3) print(x // y) # Output: 3 (floor division) 2. Assignment Operators Assignment operators are used to assign values to variables. In Python, the basic assignment is done with the = operator, but Python also has combined assignment operators for performing operations and assigning the result at the same time. Operators: o = : Assign o += : Add and assign o -= : Subtract and assign o *= : Multiply and assign o /= : Divide and assign Asst. Prof. Mitul Ghediya Page | 31  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 o **= : Exponentiate and assign o //= : Floor divide and assign o %= : Modulus and assign Example: x = 5 x += 3 # Equivalent to x = x + 3 print(x) # Output: 8 3. Comparison Operators Comparison operators are used to compare two values and return a Boolean value (True or False). Operators: o == : Equal to o != : Not equal to o > : Greater than o < : Less than o >= : Greater than or equal to o y) # Output: True print(x < y) # Output: False 4. Logical Operators Logical operators are used to combine conditional statements and return a Boolean value. Operators: o and : Returns True if both statements are true o or : Returns True if one of the statements is true o not : Reverses the result; returns False if the result is true Example: x = 10 y = 5 print(x > 5 and y < 10) # Output: True print(x < 5 or y > 10) # Output: False print(not (x == y)) # Output: True Asst. Prof. Mitul Ghediya Page | 32  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 5. Identity Operators Identity operators are used to check if two objects are the same (i.e., if they occupy the same memory location). Operators: o is : Returns True if both variables refer to the same object o is not : Returns True if they do not refer to the same object Example: x = [1, 2, 3] y = [1, 2, 3] z = x print(x is z) # Output: True (x and z point to the same list) print(x is y) # Output: False (x and y are different objects) print(x == y) # Output: True (they have the same content) 6. Membership Operators Membership operators are used to test if a value is part of a sequence, like a list, string, or tuple. Operators: o in : Returns True if a value is found in the sequence o not in : Returns True if a value is not found in the sequence Example: fruits = ["apple", "banana", "cherry"] print("banana" in fruits) # Output: True print("grape" not in fruits) # Output: True 7. Bitwise Operators Bitwise operators are used to perform bit-level operations on integers. They work on the binary representations of the numbers. Operators: o & : AND o | : OR o ^ : XOR o ~ : NOT (inverts all bits) o > : Right shift (shifts bits to the right by a specified number of places) Example: x = 5 # 0b101 y = 3 # 0b011 print(x & y) # Output: 1 (0b001, bitwise AND) print(x | y) # Output: 7 (0b111, bitwise OR) print(x ^ y) # Output: 6 (0b110, bitwise XOR) print(~x) # Output: -6 (bitwise NOT) Conclusion Python provides a variety of operators that can be used to perform different types of operations, including arithmetic, comparison, logical, identity, membership, and bitwise operations. These operators allow developers to manipulate and evaluate data efficiently, making Python a powerful language for various computational tasks. Asst. Prof. Mitul Ghediya Page | 34  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Type Casting in Python (Implicit and Explicit) Type Casting is the process of converting one data type into another. In Python, type casting is used when you want to perform operations between variables of different data types. Python provides two main types of type casting: Implicit Type Casting (automatic) and Explicit Type Casting (manual). 1. Implicit Type Casting in Python Implicit Type Casting occurs when Python automatically converts one data type into another without any user involvement. Python handles this automatically when it senses that the conversion is necessary. Example: a = 7 # Integer b = 3.0 # Float c = a + b # Python automatically converts 'a' to float for addition print(c) # Output: 10.0 print(type(c)) # Output: d = a * b # Python automatically converts 'a' to float for multiplication print(d) # Output: 21.0 print(type(d)) # Output: Explanation: In this example, Python automatically converts the integer a to a float to perform the operation with b (which is a float). The result is of type float. 2. Explicit Type Casting in Python Explicit Type Casting occurs when the programmer manually converts one data type into another by using predefined functions like int(), float(), and str(). Common Functions for Explicit Type Conversion: int(): Converts a float or string to an integer. float(): Converts an integer or string to a float. str(): Converts an integer or float to a string. Asst. Prof. Mitul Ghediya Page | 35  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Examples of Explicit Type Casting: Convert Int to Float: a = 5 n = float(a) # Manually casting 'a' to a float print(n) # Output: 5.0 print(type(n)) # Output: Convert Float to Int: a = 5.9 n = int(a) # Manually casting 'a' to an integer print(n) # Output: 5 print(type(n)) # Output: Note: Converting a float to an integer discards the decimal part. Convert Int to String: a = 5 n = str(a) # Manually casting 'a' to a string print(n) # Output: '5' print(type(n)) # Output: Explanation: The integer a is converted to a string "5". The result is of type str. 3. Summary of Implicit vs Explicit Casting Feature Implicit Type Casting Explicit Type Casting Initiated by Automatically by Python Manually by the programmer User No user involvement required Requires user involvement Involvement Happens during operations with mixed Used when you need to convert Use Case data types between types a + b where a is an int and b is a Example float(5) to convert 5 into a float float Conclusion Asst. Prof. Mitul Ghediya Page | 36  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Type casting in Python allows you to convert data types, either implicitly or explicitly, to perform operations between variables of different types. Implicit type casting is automatically handled by Python, while explicit type casting is controlled by the user using predefined functions like int(), float(), and str(). Asst. Prof. Mitul Ghediya Page | 37  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 If Statement, Elif Statement, and Nested If Statement in Python In Python, decision-making is a critical part of programming. Conditional statements allow the code to make decisions and execute specific blocks of code based on conditions. This is primarily achieved using the if, elif, and else statements. 1. If Statement The if statement is the simplest form of a decision-making statement. It checks a condition, and if the condition evaluates to True, a block of code is executed. Syntax: if condition: # block of code to execute if the condition is true Example: num = int(input("Enter a number: ")) if num % 2 == 0: print("The number is even.") Output: Enter a number: 10 The number is even. 2. If-Else Statement The if-else statement adds an additional block of code that is executed if the condition evaluates to False. Syntax: if condition: # block of code to execute if the condition is true else: # block of code to execute if the condition is false Example: num = int(input("Enter a number: ")) if num % 2 == 0: print("The number is even.") else: print("The number is odd.") Asst. Prof. Mitul Ghediya Page | 38  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Output: Enter a number: 7 The number is odd. 3. Elif Statement The elif statement (short for "else if") is used when multiple conditions need to be checked. If the if condition is False, the program checks the elif condition. If it’s True, the corresponding block of code is executed. Multiple elif statements can be chained together. Syntax: if condition1: # block of code to execute if condition1 is true elif condition2: # block of code to execute if condition2 is true elif condition3: # block of code to execute if condition3 is true else: # block of code to execute if none of the above conditions are true Example: marks = int(input("Enter your marks: ")) if marks > 85: print("Grade A") elif marks > 60: print("Grade B") elif marks > 40: print("Grade C") else: print("Grade F") Output: Enter your marks: 72 Grade B 4. Nested If Statement A nested if is an if statement inside another if statement. It allows the program to check multiple conditions even after an initial condition is found to be true. Syntax: python Asst. Prof. Mitul Ghediya Page | 39  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 if condition1: # block of code for condition1 if condition2: # block of code for condition2 else: # block of code if condition2 is false else: # block of code if condition1 is false Example: num = int(input("Enter a number: ")) if num > 0: print("The number is positive.") if num % 2 == 0: print("The number is even.") else: print("The number is odd.") else: print("The number is negative or zero.") Output: Enter a number: 12 The number is positive. The number is even. 5. Repetition (Using Loops with Conditional Statements) Conditional statements are often combined with loops (such as for or while) to repeat certain actions based on conditions. The repetition of conditions enables iterative decision- making. Example: for i in range(1, 6): if i % 2 == 0: print(f"{i} is even.") else: print(f"{i} is odd.") Output: 1 is odd. 2 is even. 3 is odd. 4 is even. 5 is odd. Asst. Prof. Mitul Ghediya Page | 40  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Conclusion If statements are used for single conditional checks. Elif statements are used for multiple conditional checks. Nested if statements allow for more complex decision-making where conditions depend on each other. Repetition can be achieved by combining loops with conditional statements to check conditions iteratively. Asst. Prof. Mitul Ghediya Page | 41  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 Python Loops In Python, loops are used to execute a block of code repeatedly as long as a certain condition is met. This allows you to automate repetitive tasks efficiently. 1. The while Loop A while loop keeps executing a block of code as long as the specified condition remains true. It checks the condition before each iteration and runs the code only if the condition is true. Syntax: while condition: # Code block to execute Example 1: count = 1 while count 0: print("Number is:", number) number -= 1 print("Liftoff!") Output: Number is: 10 Number is: 9 Number is: 8... Liftoff! Asst. Prof. Mitul Ghediya Page | 42  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 2. The for Loop The for loop in Python is used to iterate over a sequence (such as a list, tuple, dictionary, set, or string). It runs a block of code for each item in the sequence. Syntax: for variable in iterable: # Code block to execute Example 1: fruits = ["apple", "banana", "cherry"] for fruit in fruits: print(fruit) Output: banana cherry Example 2: numbers = [1, 2, 3, 4, 5] sum = 0 for number in numbers: sum += number print("Total sum:", sum) Output: Total sum: 15 3. Nested Loops A nested loop is a loop inside another loop. The inner loop runs completely each time the outer loop runs once. Syntax: for outer_variable in outer_iterable: for inner_variable in inner_iterable: # Code block to execute Example (for loops): rows = 5 columns = 4 Asst. Prof. Mitul Ghediya Page | 43  Course Code: 2040237101 Course Name: Python Programming SEMESTER: 11 for i in range(1, rows + 1): # Outer loop for rows for j in range(1, columns + 1): # Inner loop for columns print(f"({i},{j})", end=" ") print() # Move to the next line after each row Output: (1,1) (1,2) (1,3) (1,4) (2,1) (2,2) (2,3) (2,4) (3,1) (3,2) (3,3) (3,4) (4,1) (4,2) (4,3) (4,4) (5,1) (5,2) (5,3) (5,4) Example (while loops): i = 1 while i