惯性聚合 高效追踪和阅读你感兴趣的博客、新闻、科技资讯
阅读原文 在惯性聚合中打开

推荐订阅源

量子位
小众软件
小众软件
S
SegmentFault 最新的问题
人人都是产品经理
人人都是产品经理
博客园 - 【当耐特】
博客园 - 三生石上(FineUI控件)
C
Check Point Blog
S
Schneier on Security
Microsoft Azure Blog
Microsoft Azure Blog
N
Netflix TechBlog - Medium
Engineering at Meta
Engineering at Meta
GbyAI
GbyAI
罗磊的独立博客
有赞技术团队
有赞技术团队
V
V2EX
Y
Y Combinator Blog
博客园 - 叶小钗
让小产品的独立变现更简单 - ezindie.com
让小产品的独立变现更简单 - ezindie.com
freeCodeCamp Programming Tutorials: Python, JavaScript, Git & More
Cyber Security Advisories - MS-ISAC
Cyber Security Advisories - MS-ISAC
F
Fortinet All Blogs
W
WeLiveSecurity
OSCHINA 社区最新新闻
OSCHINA 社区最新新闻
Stack Overflow Blog
Stack Overflow Blog
The Cloudflare Blog
S
Security @ Cisco Blogs
TaoSecurity Blog
TaoSecurity Blog
MyScale Blog
MyScale Blog
Hugging Face - Blog
Hugging Face - Blog
cs.AI updates on arXiv.org
cs.AI updates on arXiv.org
www.infosecurity-magazine.com
www.infosecurity-magazine.com
PCI Perspectives
PCI Perspectives
H
Heimdal Security Blog
Schneier on Security
Schneier on Security
Security Latest
Security Latest
AWS News Blog
AWS News Blog
月光博客
月光博客
Security Archives - TechRepublic
Security Archives - TechRepublic
Recent Announcements
Recent Announcements
Google DeepMind News
Google DeepMind News
博客园 - Franky
Cisco Talos Blog
Cisco Talos Blog
T
Threat Research - Cisco Blogs
M
MIT News - Artificial intelligence
T
Troy Hunt's Blog
N
News and Events Feed by Topic
Cloudbric
Cloudbric
Scott Helme
Scott Helme
云风的 BLOG
云风的 BLOG
Attack and Defense Labs
Attack and Defense Labs

DEV Community

Authentication Security Deep Dive: From Brute Force to Salted Hashing (With Java Examples) Why AI Systems Don’t Fail — They Drift Spilling beans for how i learn for exam😁"Reinforcement Learning Cheat Sheet" I Replaced Chrome with Safari for AI Browser Automation. Here's What Broke (and What Finally Worked) How Python Borrows Other People's Work The $40 Architecture: Processing 1 Billion API Requests with 99.99% Uptime Vibe Coding: A Workflow Guide (From Zero to SaaS) Most webhook security guides protect the wrong side. The scary part is delivery. Headless CMS for TanStack Start: Build a Blog with Cosmic EU Age Verification App "Hacked in 2 Minutes" — What Actually Happened Comfy Cloud’s delete function does not actually remove files Running AI Models on GPU Cloud Servers: A Beginner Guide Event-driven media intelligence with AWS Step Functions and Bedrock I scored 500 AI prompts across 8 quality dimensions — here's what broke How to Call Google Gemini API from Next.js (Free Tier, No Backend Needed) The Portal Protocol: Reclaiming Human Connection in the Age of AI How to Fix Your Team's Scattered Knowledge Problem With a Self-Hosted Forum Intro to tc Cloud Functors: A Graph-First Mental Model for the Modern Cloud Designing Multi-Tenant Backends With Both Ownership and Team Access I Built a Neumorphic CSS Library with 77+ Components — Here's What I Learned PostgreSQL Performance Optimization: Why Connection Pooling Is Critical at Scale Cómo construí un SaaS multi-rubro para gestionar expensas en Argentina con FastAPI + Vue 3 🚀 I Built an Ethical Hacking Scanner Tool – Open Source Project I Replaced /usage and /context in Claude Code With a Single Statusline A Pythonic Way to Handle Emails (IMAP/SMTP) with Auto-Discovery and AI-Ready Design I Collected 8.9 Million Polymarket Price Points — Here's What I Found About How Markets Really Move EcoTrack AI — Carbon Footprint Tracker & Dashboard Everyone's Using AI. No One Agrees How. 5 self-hosted ebook managers worth trying in 2026 Building Your First AI Agent with LangChain: From Chatbot to Autonomous Assistant Common SOC 2 Failures (Real World) Stop Vibe-Checking Your AI App: A Practical Guide to Evals How to Use SonarQube and SonarScanner Locally to Level Up Your Code Quality Your Next To-Do App Is Dead — I Replaced Mine with an OpenClaw AI Sign a Nostr event in 60 lines of Python using coincurve — no nostr-sdk, no nbxplorer, no rust toolchain ITGC Audit Explained Like You’re in Big 4 Patch Tuesday abril 2026: Microsoft parcha 163 vulnerabilidades y un zero-day en SharePoint Stop scraping everything: a better way to track competitor price changes Listing on MCPize + the Official MCP Registry while routing payments OUTSIDE the marketplace — how I kept 100% of my x402 revenue Building an AI-Powered Risk Intelligence System Using Serverless Architecture Why We Ripped Function Overloading Out of Our AI Toolchain Testing AI-Generated Code: How to Actually Know If It Works SaaS Churn Is Killing Your Business. Here Is What to Do About It (Without a Support Team) The Speed of AI Is No Longer Linear - And Self-Improving Models Are Why How to Implement RBAC for MCP Tools: A Practical Guide for Engineering Teams From Standard Quote to Persuasive Proposal: AI Automation for Arborists I built a CLI that scaffolds complete multi-tenant SaaS apps Axios CVE-2025–62718: The Silent SSRF Bug That Could Be Hiding in Your Node.js App Right Now The dashboard that ended our friendship Data Pipelines Explained Simply (and How to Build Them with Python) The Hidden Cost of AI Systems Nobody Talks About. undefined vs undeclared, and how typeof behaves Switching from file-based jobs to NATS/Kafka in Rust without changing code io_uring Adventures: Rust Servers That Love Syscalls Why Agentic AI is Killing the Traditional Database The POUR principles of web accessibility for developers and designers Quantum Neural Network 3D — A Deep Dive into Interactive WebGL Visualization How To Install Caveman In Codex On macOS And Windows Automation Pipeline Reliability: Why Your Workflow Breaks When Nobody Is Watching I Built an 'Open World' AI Coding Agent — It Works From ANY Folder From Freelancing to Product: A Tech Service Company's SaaS Transformation China's AI Giants: Adding Tencent Hunyuan & ByteDance Doubao to AI University (74 Providers) On the Vibe Coders and Their Lies clerk: Auto-Summarize Your Claude Code Sessions AI Weekly — 2026/04/10–04/17 | The Model Lockdown Is Here, but the Toolchain Is the Real Battleground AI 週報 — 2026/04/10–2026/04/17 模型封鎖潮來了,但工具鏈才是真戰場 Maybe this is how Open-Source apps are born... 🚀 Fine-Tune LLMs with LoRA and QLoRA: 2026 Guide tRPC v11 + Next.js App Router: End-to-End Type Safety Without the Boilerplate ShadCN UI in 2026: Why I Stopped Installing Component Libraries and Started Owning My Components SaaS Billing in React Server Components: Stripe + Supabase Without a Single `useEffect` Join our DEV Weekend Challenge — $1,000 in Prizes Across TEN winners! Submissions Due April 20 at 6:59 AM UTC. Implementing FSRS Spaced Repetition in Flutter + Supabase — Adding Memory Science to an AI Learning App "I Texted My Localhost From the Train — Claude Code Fixed the Bug Before I Got Home" I Built a Sales Prep AI and It Went Deeper Than Expected Design to Code #2: One JSON, Eleven Outputs Solving the 100M-Row Problem: A Summary Table Pattern for High-Volume Push Notification Logs Flutter Web With Wasm: What Actually Changes For Developers I Built 50 Royalty-Free Soundtracks for My Side Project in a Weekend Using AI Music Generation The Vibe Coding Security Checklist: 7 Things to Check Before You Ship Stop Letting Googlebot Guess Fix Your React App's SEO Right Desconstruindo o Streaming do LinkedIn: Como Criar um Engine de Extração de Vídeo de Alta Performance com HLS e FFmpeg (EDA Part-1) EDA (Exploratory Data Analysis) Explained With Real Life — Why Looking at Your Data Is the Most Important Step in Machine Learning Brand Relationship Management at Scale: Our 4-Touch Outreach System for 200+ Brands Why String.fromEnvironment() Might Return an Empty String in Dart JGuardrails 1.0.0 — Hardening Java LLM Apps Against Jailbreaks, Toxicity, and Prompt Injection Plan and Schedule a Full Week of Threads Content From One Claude Conversation Coding Cat Oran Ep3, Five Tables Changed Everything Updated: BFF Pattern I'm done watching freelancers get buried by 200 proposals. So I'm building the alternative. This is my first post BFS Algorithm in Java Step by Step Tutorial with Examples Tracking LLM Pricing Monthly: An Open Dataset for 22 AI Models How We Measure Content ROI on a Comparison Site: Revenue Attribution Without Perfect Data Introducing Nova AI Ops: The AI-Native Operating System for SRE Teams I built a free desktop video downloader for Windows — Grabbit How Talkie OCR Helps Vision-Impaired & Dyslexic Users Read the World Around Them VRCFaceTracking安装和iPhone面捕配置教程,有bug Even CrowdStrike Can't See Your Agents The Automation Gold Rush: What n8n Workflows and Claude Are Opening Up for Developers Right Now
Getting Started with Python: A Practical Introduction for Beginners
Jason Ndalam · 2026-05-06 · via DEV Community

Welcome to the world of Python! If you are just starting your programming journey, you have chosen the perfect language. This beginner-friendly guide will teach you the fundamentals of Python in a simple, practical, and engaging way.


1. Introduction

What is Python? Python is a powerful, flexible, and dynamically typed programming language created by Guido van Rossum and first released in 1991. It is widely considered one of the most loved and used programming languages in the world.

Why is it Popular? Imagine you are cooking: would you rather follow a long, complex recipe full of jargon, or a simple one written in plain English? Python is designed to be highly readable, looking almost like spoken English rather than complex machine code. It allows you to write fewer lines of code to achieve the same result as other languages, like Java.

Python is highly versatile and serves as a "multi-tool" for a wide range of real-world scenarios. It is used for web development (powering apps like Instagram and YouTube), data analysis, AI, machine learning, and system scripting (automating repetitive computer tasks). It has even been used by NASA for rocket logic!


2. Installation

Before writing code, you need to set up Python on your computer.

Step-by-Step Guide:

  1. Download Python: For Windows users, you can safely download the latest version (like Python 3.12) directly from the Microsoft Store. (Note: You can also download it from the official website at (https://www.python.org/downloads/), which is standard industry practice, though not explicitly linked in the provided sources. Please independently verify this URL.

  2. Install: Run the downloaded installer. It is critical during this step to ensure Python is added to your system's "PATH" environment variable, which allows your system to recognize Python commands in your terminal.

Verify Installation: Once installed, open your Command Prompt (CMD) or terminal. Type the following command and press Enter to verify your installation:
python --version
(Note for Mac and Linux users: You may need to use python3 --version.)


3. Your First Program: Hello World

In Python, writing your first program is incredibly simple and avoids confusing symbols or extra fluff. Let's write a program that displays a message on the screen.
print("Hello, World!")

What the code does: Think of the print() command as a megaphone. You are giving Python a clear, direct instruction: "Hey, shout this message on the screen!". Because Python is an interpreted language, it runs your code line by line and immediately outputs the result.


4. Comments in Python

Comments are notes left in the code for humans to read. Python ignores them when running the program, but they are crucial for explaining what your logic does.

Single-Line Comments: You can create a single-line comment by using the hash symbol #. As a best practice, try to keep your comment lines from exceeding 72 characters.

# This line is ignored by Python
print("Hello!")  # You can also place comments after code

Enter fullscreen mode Exit fullscreen mode

Multi-Line Comments: For longer explanations, you can use triple quotes (""") to create a multi-line string, which Python treats as a multi-line comment when not assigned to a variable.

"""
This is a
multi-line comment.
It is great for long explanations!
"""

Enter fullscreen mode Exit fullscreen mode


5. Variables

Imagine your brain is a giant notebook; when you learn something new, you store it under a label. In Python, variables act as labelled boxes or containers where you store data to open and use later.

Rules for Naming Variables:

  • Must start with a letter (a–z, A–Z) or an underscore _ (e.g., _my_age).
  • Cannot start with a number (e.g., 1user is invalid).
  • Can only contain alphanumeric characters and underscores.
  • Names are case-sensitive (name and NAME are completely different).
  • Tip: Use descriptive names in snake_case (e.g., user_name instead of just x).

Examples of Different Data Types: Because Python is dynamically typed, you don't need to specify the data type—Python figures it out automatically based on the value you assign.

Integer (int) - Whole numbers like counting apples
age = 25

Float (float) - Decimal numbers like measuring height
height = 5.9

String (str) - Text enclosed in single or double quotes
name = "Alice"

Boolean (bool) - True or False values, like a light switch (ON/OFF)
is_logged_in = True


6. Operators

Operators allow you to perform calculations or compare data in Python.
Arithmetic Operators: Used to perform standard mathematical calculations.

a = 10
b = 3
print(a + b)   # Addition: outputs 13
print(a - b)   # Subtraction: outputs 7
print(a * b)   # Multiplication: outputs 30
print(a / b)   # Division: outputs 3.333...

Enter fullscreen mode Exit fullscreen mode

Comparison Operators: Used to compare two values. They act as "Yes/No" questions and always result in a Boolean (True or False).

x = 10
y = 9
print(x > y)   # Greater than: True
print(x == y)  # Equal to: False
print(x != y)  # Not equal to: True

Enter fullscreen mode Exit fullscreen mode

Logical Operators: Used to check multiple conditions at once using and and or.

age = 20
has_ticket = True`
# 'and' means both conditions MUST be True`
if age >= 18 and has_ticket:
    print("Entry allowed.")
else:
    print("Entry denied.")

Enter fullscreen mode Exit fullscreen mode


Conclusion

You've just taken your first steps into Python! We covered how Python's readable syntax makes programming feel like writing English, how to install and run your first "Hello, World!" program, and how to use foundational concepts like variables, data types, and operators.