Introduction and Syntax of Python Programming [ Scripting Language DI02000101]

Python Programming for Beginners: Introduction, Syntax & Practical Examples

Introduction to Python

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Python is a powerful, high-level, and easy-to-learn programming language. It is widely used for web development, data analysis, artificial intelligence, automation, and more. Python’s simplicity and readability make it an ideal choice for beginners.

History of Python

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Python was created by Guido van Rossum and first released in 1991. It was designed to emphasize code readability and ease of use. Over the years, Python has evolved into one of the most popular programming languages in the world

Python Features

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Simple and Easy to Learn – Python’s syntax is clean and resembles English.
Interpreted Language – Code is executed line by line.
Dynamically Typed – No need to declare variable types explicitly.
Object-Oriented – Supports classes and objects.
Extensive Libraries – Comes with a rich set of built-in modules and libraries.
Portable – Python code can run on multiple platforms without modification.
Open Source – Freely available and community-supported.

Python Applications

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Web Development (Django, Flask)
Data Science & Machine Learning (Pandas, NumPy, TensorFlow)
Automation & Scripting

Game Development
Cybersecurity
Embedded Systems & IoT

Installing Python

To get started with Python, you need to install it on your system.

Download Python from the official website: https://www.python.org
Install it following the on-screen instructions.
Verify installation by running python --version in the terminal or command prompt.

Basic Structure of a Python Program

Python programs typically follow this structure:

# This is a comment
print("Hello, World!") # Print statement

Keywords and Identifiers

Keywords

Keywords are reserved words in Python that have predefined meanings. Examples include if, else, while, for, import, class, etc.

Identifiers

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- Identifiers are names used for variables, functions, and classes. They must:
-Start with a letter (A-Z or a-z) or an underscore (_)
-Contain letters, digits (0-9), or underscores
- Not be a Python keyword

Example:

my_variable = 10  # Valid identifier
123var = 5  # Invalid identifier (cannot start with a number)l

Variables and Type Casting

Variables

Variables are used to store data. Python allows dynamic typing, meaning you don’t need to specify the type of a variable explicitly.

x = 10      # Integer
y = "Hello" # String
  

Type Casting

Converting one data type into another:

x = 5
float_x = float(x)  # Converts integer to float
print(float_x)  # Output: 5.0

Input-Output Functions

input()

Used to take user input.

name = input("Enter your name: ")
print("Hello, " + name)

print()

Displays output.

print("Hello, World!")

Data Types in Python

Python has several built-in data types:

Numbers

Includes integers, floating-point numbers, and complex numbers.

x = 10   # Integer
y = 3.14 # Float
z = 2 + 3j # Complex number

Strings

A sequence of characters enclosed in quotes.

s = "Python"
print(s[0])  # Output: P

List

Ordered, mutable collection of items.

my_list = [1, 2, 3, "hello"]
print(my_list[2])  # Output: 3

Tuple

Ordered, immutable collection.

tuple_example = (1, 2, 3, "hello")
print(tuple_example[1])  # Output: 2

Set

Unordered collection of unique items.

my_set = {1, 2, 3, 4, 4}
print(my_set)  # Output: {1, 2, 3, 4}

Dictionary

Key-value pairs.

dict_example = {"name": "Alice", "age": 25}
print(dict_example["name"])  # Output: Alice

Literals, Constants, and Identifiers

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Literals: Fixed values like 10, 3.14, "Hello".
Constants: Variables assigned fixed values (conventionally in uppercase).
Identifiers: Names given to variables, functions, and classes.

Program Solving Practice

Example 1: Simple Input and Output

name = input("Enter your name: ")
print("Welcome, " + name + "!")
  

Example 2: Data Type Conversion

x = input("Enter a number: ")
y = int(x) + 5
print("Result:", y)
  

Example 3: Using Lists and Dictionaries

students = {"Alice": 85, "Bob": 90, "Charlie": 78}
print("Alice's score:", students["Alice"])  # Output: 85
  

Python is a beginner-friendly language with a simple syntax and powerful features. By understanding its basics, you can start writing efficient programs quickly.