Week 1 - Day 1: Intro to Programming

📚 Learning Objectives

By the end of this session, you will be able to:

Understand what programming is and why it matters
Install Python and set up your development environment
Write and run your first Python program
Use the Python REPL for interactive coding
Understand basic Python syntax and structure

📖 Core Concepts (2 Hours)

What is Programming?

Programming is giving instructions to a computer to solve problems. It's the foundation of all software, automation, and DevOps.

Instructions: Computers follow step-by-step commands
Languages: Python, JavaScript, Java, Go, etc.
Why Python: Simple syntax, powerful libraries, DevOps standard
DevOps Use: Automation scripts, CI/CD pipelines, infrastructure as code

Why Python for DevOps?

                    
# Python is used in:
# - Automation scripts (Ansible, Fabric)
# - Cloud SDKs (AWS Boto3, Azure SDK)
# - CI/CD tools (Jenkins pipelines)
# - Infrastructure as Code (Pulumi)
# - Monitoring (custom metrics, alerts)
# - Web APIs (Flask, FastAPI)

# 90% of DevOps tools have Python support!
                    
                

Installing Python

                    
# Check if Python is installed
python3 --version
# or
python --version

# Installation Options:

# Ubuntu/Debian Linux
sudo apt update
sudo apt install python3 python3-pip

# macOS (using Homebrew)
brew install python3

# Windows
# Download from python.org
# Check "Add Python to PATH" during installation

# Verify installation
python3 --version
# Python 3.11.x (or higher)

pip3 --version
# pip 23.x.x
                    
                

Your First Python Program

                    
# Create a file: hello.py

# The classic first program
print("Hello, World!")

# Print multiple things
print("Welcome to Python!")
print("Let's learn DevOps!")

# Run the program:
# python3 hello.py

Understanding print()

                    
# print() outputs text to the screen

# Basic usage
print("Hello")

# Multiple items
print("Python", "is", "awesome")
# Output: Python is awesome

# With separator
print("2024", "01", "15", sep="-")
# Output: 2024-01-15

# Without newline
print("Loading", end="")
print("...")
# Output: Loading...

# Empty line
print()
                    
                

The Python REPL

                    
# REPL = Read-Eval-Print-Loop
# Interactive Python shell for testing code

# Start REPL
python3

# You'll see:
# Python 3.11.x
# >>>

# Try these commands:
>>> print("Hello from REPL!")
Hello from REPL!

>>> 2 + 2
4

>>> "Python" * 3
'PythonPythonPython'

>>> len("DevOps")
6

# Exit REPL
>>> exit()
# or Ctrl+D
                    
                

Comments in Python

                    
# Single line comment - use #
# This is a comment
print("Hello")  # This is an inline comment

# Multi-line comments use triple quotes
"""
This is a multi-line comment.
It can span multiple lines.
Great for documentation!
"""

'''
Single quotes also work
for multi-line comments.
'''

# Comments are ignored by Python
# Use them to explain your code!
                    
                

Python Syntax Basics

                    
# Python uses INDENTATION for code blocks
# No curly braces {} like other languages

# Correct indentation (4 spaces)
if True:
    print("This is indented")
    print("Same block")

# Wrong indentation causes errors!
# if True:
# print("Error!")  # IndentationError!

# Case sensitive
Name = "Alice"
name = "Bob"
# These are DIFFERENT variables!

# Statements end with newline (no semicolons needed)
print("Line 1")
print("Line 2")
                    
                

🔬 Hands-on Lab (2.5 Hours)

Lab 1: Python Installation

Install Python 3 on your system
Verify with python3 --version
Verify pip with pip3 --version
Open Python REPL with python3

Lab 2: REPL Exploration

Start the Python REPL
Try basic math: 10 + 5, 100 / 4
Print messages: print("Your name")
Exit with exit()

                    
# Lab 2: Practice in REPL
>>> 10 + 5
15

>>> 100 - 25
75

>>> 8 * 7
56

>>> 100 / 4
25.0

>>> 17 // 3    # Integer division
5

>>> 17 % 3     # Remainder (modulo)
2

>>> 2 ** 10    # Power (2^10)
1024

>>> print("I am learning Python!")
I am learning Python!
                    
                

Lab 3: First Script

Create a file called intro.py
Add print statements
Run with python3 intro.py
Modify and re-run

                    
# Lab 3: Create intro.py

# intro.py
print("=" * 40)
print("  Welcome to DevOps Python Course!")
print("=" * 40)
print()
print("Day 1: Introduction to Programming")
print("Today we learned:")
print("  - What programming is")
print("  - How to install Python")
print("  - Using the REPL")
print("  - Writing our first script")
print()
print("Let's continue to Day 2!")
print("=" * 40)

# Run: python3 intro.py
                    
                

Lab 4: Code Editor Setup

Install VS Code (if not installed)
Install Python extension
Create a Python file and run it
Use the integrated terminal

📝 Practice Exercises

Write a program that prints your name and favorite language
Use the REPL to calculate: 15 * 8 + 22
Create a script that prints a box with your name inside
Experiment with print() using sep and end parameters

💡 DevOps Relevance

Why this matters:

Scripts: Automate repetitive tasks
REPL: Quick testing and debugging
print(): Logging and debugging output
Comments: Document automation scripts

✅ Day 1 Checklist

Python 3 installed and working
Can use the Python REPL
Wrote and ran first Python script
Understand print() function
Know how to write comments
Understand Python indentation rules