Python Use Cases

Introduction

Python’s versatility makes it suitable for almost every domain in software development.

AI & Machine Learning

from sklearn.linear_model import LinearRegression
import numpy as np

# House price prediction
X = np.array([[500], [750], [1000], [1500], [2000]])
y = np.array([150000, 200000, 250000, 350000, 450000])

model = LinearRegression()
model.fit(X, y)
print(model.predict([[1200]]))  # ~290,000

Libraries: TensorFlow, PyTorch, scikit-learn, Keras, Hugging Face

Companies: Google, OpenAI, Tesla, Netflix

Web Development

from flask import Flask, jsonify

app = Flask(__name__)

@app.route('/api/users', methods=['GET'])
def get_users():
    users = [{"id": 1, "name": "Alice"}, {"id": 2, "name": "Bob"}]
    return jsonify(users)

Frameworks: Django, Flask, FastAPI, Tornado

Companies: Instagram (Django), Pinterest, Spotify (Flask)

Automation & Scripting

import os
import re

for filename in os.listdir("/downloads/reports"):
    match = re.match(r"report_(\d{4})_(\d{2})\.pdf", filename)
    if match:
        year, month = match.groups()
        new_name = f"{year}-{month}-report.pdf"
        os.rename(
            os.path.join(folder, filename),
            os.path.join(folder, new_name)
        )

Libraries: Selenium, PyAutoGUI, Playwright

Data Science

import pandas as pd
import matplotlib.pyplot as plt

df = pd.read_csv("sales_2024.csv")
top_products = df.groupby("product")["revenue"].sum().sort_values(ascending=False).head(5)
top_products.plot(kind="bar", title="Top 5 Products by Revenue")
plt.savefig("top_products.png")

Libraries: Pandas, NumPy, Matplotlib, Seaborn, Plotly, Jupyter

Cybersecurity

import socket

def scan_port(host, port):
    with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
        s.settimeout(0.5)
        result = s.connect_ex((host, port))
        return port, "OPEN" if result == 0 else "CLOSED"

Libraries: Scapy, Paramiko, Cryptography, Scapy

DevOps

import boto3

ec2 = boto3.client('ec2', region_name='us-east-1')
response = ec2.describe_instances(
    Filters=[{'Name': 'instance-state-name', 'Values': ['running']}]
)

Tools: Ansible, boto3, Fabric, Docker SDK

Why It Matters

Python’s diverse applications make it a valuable skill across many career paths.

Interview Questions

Q1: What are the main domains where Python is used?

A: Python is used in AI/ML, web development, data science, automation, cybersecurity, DevOps, finance, and IoT/embedded systems.

Q2: What makes Python suitable for AI/ML?

A: Extensive libraries (TensorFlow, PyTorch, scikit-learn), readability (data scientists can focus on algorithms), and integration with C/C++ for performance.

Practice Exercises

Research and list 3 companies using Python in production.
Write a simple automation script for a repetitive task you do.
Build a basic web API with Flask or FastAPI.