Introduction to Python

Introduction to Python

• Creator: Guido van Rossum (1991)
• Type: Interpreted, high-level, object-oriented language.
• Why use Python?
  • Works on Windows, Mac, Linux
  • Simple English-like syntax
  • Fewer lines of code
  • Supports procedural, OOP, and functional styles
  • Used in web, AI, data, and automation

Compiler vs Interpreter

Python Syntax Basics

• Python uses indentation (spaces) instead of braces { }.
• Standard: 4 spaces per block.
• Inconsistent indentation → error.

if 5 > 2:
    print('Five is greater than two!')

Comments

# Single line comment

"""
Multi-line
comment
"""

Comments are ignored by the interpreter and used for clarity.

Variables

• Created automatically when a value is assigned.
• Dynamically typed (no need for type declaration).

x = 100
y = 'Python'

Rules:

• Start with letter or underscore.
• No spaces or special characters.
• Case-sensitive: age ≠ Age.

Type casting:

x = str(3)
y = int(3)
z = float(3)
print(type(x))

Multiple Assignments & Unpacking

x, y, z = 'Red', 'Green', 'Blue'
a = b = c = 'Python'

fruits = ['apple', 'banana', 'cherry']
x, y, z = fruits

Printing Output

x, y, z = 'Python', 'is', 'awesome'
print(x, y, z)