Python Basics

1. Getting Started

To run Python, you need to install it from python.org, or use an online IDE like Replit, Google Colab, or Jupyter Notebooks.

print("Hello, World!")

This line uses the built-in print() function to output text to the screen.

2. Variables and Data Types

Variables store data. You don't need to declare the type explicitly in Python:

name = "Alice"        # String
age = 25              # Integer
height = 5.6          # Float
is_student = True     # Boolean
    

Common data types include:

• int – integers (e.g., 1, 100)
• float – decimals (e.g., 3.14)
• str – strings (e.g., "Hello")
• bool – Boolean values (True or False)

3. Operators

Python supports arithmetic and logical operations:

# Arithmetic
x = 10 + 5       # 15
y = 20 - 8       # 12
z = 4 * 3        # 12
w = 15 / 3       # 5.0

# Comparison
a == b, a != b, a > b, a < b

# Logical
and, or, not
    

4. Control Flow: if, elif, else

Python uses indentation (usually 4 spaces) to define blocks of code:

if age > 18:
    print("Adult")
elif age == 18:
    print("Just turned adult")
else:
    print("Minor")
    

5. Loops: for and while

Use loops to repeat actions:

# For loop
for i in range(5):
    print(i)   # 0 to 4

# While loop
count = 0
while count < 5:
    print(count)
    count += 1
    

6. Functions

Functions allow code reuse and organization:

def greet(name):
    return f"Hello, {name}!"

print(greet("Alice"))
    

7. Data Structures

Python has built-in structures for storing collections:

• List – ordered, mutable: fruits = ["apple", "banana"]
• Tuple – ordered, immutable: coords = (10, 20)
• Set – unordered, unique: colors = {"red", "blue"}
• Dict – key-value pairs: person = {"name": "Alice", "age": 25}

8. Comments and Documentation

Use # for single-line comments and triple quotes """ for documentation:

# This is a comment
"""This function greets the user"""
    

9. Importing Modules

Modules let you use additional functionality:

import math
print(math.sqrt(16))  # 4.0
    

Conclusion

Python's simplicity, combined with its powerful libraries and community support, makes it one of the best languages to start programming. Once you master the basics, you can explore areas like web development with Flask/Django, data analysis with Pandas, or automation with scripts.