Lecture: Introduction to Python and Advanced Concepts

Introduction

Sallu Bhai's son, Ballu, didn't get a Bollywood break.
Learned Python in 2 days hoping for a 90 LPA job but only got frustration.
Creation of a Python course focusing on job aspects: Python with AI, handwritten notes, latest features.
Importance of machine learning, AI, data science, web development, and general scripting.

Why Python?

Python is the most loved and easiest language (Stack Overflow).
Beginner-friendly: resembles simple English.
Comprehensive Python handbook and cheat sheet are provided.
Handwritten notes and source code are available.

Key Features of Python

Easy to understand and short development time.
Excellent for scripting, AI, ML, data science due to dedicated libraries.
Free, open-source, and high-level language.
Portable across Linux, Windows, and MacOS.

Installing Python and Visual Studio Code (VS Code)

Step 1: Download and install Python from python.org
Step 2: Add python.exe to PATH during installation.
Step 3: Install Visual Studio Code (VS Code).
Step 4: Install the Python extension in VS Code for efficient coding.

Python Fundamentals

What is Programming?

Programming languages (Python, C, C++, JavaScript) communicate with computers.
Programming languages are analogous to human languages (e.g., English, Chinese).
Programs instruct computers on what to do (e.g., summing numbers).

Basic Python Syntax

Printing & Comments:

print('Hello, World!')  # This is a comment

Types:

a = 1   # int
b = 2.0 # float
c = 'Python' # string
d = True # boolean
e = None # NoneType

Rules for Variables:
- Start with letter or underscore.
- Subsequent characters can include digits.
- No spaces or special characters allowed.

Operators and Expressions

Arithmetic Operators: +, -, *, /
Comparison Operators: ==, !=, >, <, >=, <=
Logical Operators: and, or, not
Assignment Operators: =, +=, -=, *=, /=

Built-in Functions and Modules

Type Checking:

print(type(variable))
print(float('5.6'))  # Type casting

Modules: Install and import external modules.

Advanced Concepts

String Manipulation

Creating Strings:

name = 'Python' # or "Python" or '''Python'''

String Slicing and Indexing:

print(name[0:3])  # 'Pyt'
print(name[::-1]) # 'nohtyP'

String Functions: len(), endswith(), startswith(), capitalize(), find(), replace()

Lists and Tuples

Lists:

friends = ['apple', 'mango', 1, True]
friends.append('grape')  # modifying list

Tuples:
```
values = (1, 2, 'Python')
```
List methods: .append(), .sort(), reverse(), pop()
Tuple methods: .count(), .index()

Dictionaries and Sets

Dictionary:

data = {'name': 'Harry', 'marks': 95}
data['age'] = 21  # Adding new key-value pair

Set:

unique_items = {1, 2, 2, 3}  # Duplicates not allowed
unique_items.add(4)

Conditionals and Loops

If-Else:

if age > 18:
    print("Eligible")
else:
    print("Not eligible")

Loops:

while condition:
    # code block
for item in sequence:
    # code block

Functions

Defining Functions:

def greet(name):
    print(f'Hello, {name}')

Recursion and Lambda Functions:

def factorial(n):
    if n == 0:
        return 1
    return n * factorial(n - 1)

square = lambda x: x * x

Error Handling and File I/O

Try-Except Blocks:

try:
    # Try to execute this block
except Exception as e:
    print(e)
finally:
    # This code runs no matter what

File Handling:

with open('example.txt', 'w') as file:
    file.write('Hello, World!')
with open('example.txt', 'r') as file:
    content = file.read()

Object-Oriented Programming (OOP)

Classes and Objects:

class Dog:
    def __init__(self, name, age):
        self.name = name
        self.age = age
    def bark(self):
        print('Woof!')

rex = Dog('Rex', 5)
rex.bark()

Inheritance:

class Animal:
    # Base class
class Dog(Animal):
    # Derived class

Advanced Topics

Virtual Environments: Creating isolated Python environments.

touchvenvproject

pip install virtualenv
virtualenv myprojectenv
source myprojectenv/bin/activate

Lambda Functions: Inline anonymous functions

add = lambda x, y: x + y
print(add(2, 3))  # 5

Map, Filter, Reduce: Built-in functions for applying to lists.

map(function, list)
filter(function, list)
reduce(function, list)

List Comprehensions:

[x for x in range(5)]  # [0, 1, 2, 3, 4]

Decorators:

def my_decorator(func):
    def wrapper():
        print("Something is happening before the function is called.")
        func()
        print("Something is happening after the function is called.")
    return wrapper

Useful Libraries

NumPy, Pandas: Data manipulation and analysis
Matplotlib, Seaborn: Data visualization
Flask, Django: Web development frameworks
Pillow: Image processing
OpenCV: Computer vision
Requests: Making HTTP requests

Conclusion

Emphasized the importance of practice and project-based learning.
Encouraged exploring advanced topics and building real-world projects.
Reiterated the extensive support and tutorials available for Python learners.

Introduction to Python and Advanced Concepts 🙌