Python Fundamentals: Complete Learning Roadmap

Welcome to your second brain Python reference library. This page organizes 11 comprehensive guides into a structured learning path. Follow this sequence to build unshakeable Python fundamentals before Le Wagon bootcamp (October 2026).


📍 Quick Navigation

Start here based on your level:

  • 🟢 Beginner (haven’t coded much): Start with TIER 1
  • 🟡 Intermediate (coded before): Start with TIER 2
  • 🔴 Advanced (need just the gaps): Jump to TIER 3

🎯 TIER 1: Core Language Fundamentals (Weeks 1-4)

Build the mental models you’ll use every day. Master these before touching data libraries.

#TopicPageTimeLearn
1Loops: for & whilePython-Loops2hWhen to repeat code, mental models for iteration
2Control Flow: if/elif/elsePython-Control-Flow2hDecision-making logic, boolean operators, ternary
3Functions & ModulesPython-Modules-Functions-Lists2.5hCode organization, reusability, imports
4Lists (The Workhorse)Python-Modules-Functions-Lists2.5hIndexing, slicing, methods, list operations
5List ComprehensionsPython-List-Comprehensions2hPythonic transformations, filtering, performance
6Data StructuresPython-Data-Structures2hLists, dicts, sets, tuples—when to use each

Subtotal: ~13 hours
After TIER 1 you can: Write clean functions, loop over data, understand basic Python code.


🚀 TIER 2: Production-Grade Fundamentals (Weeks 5-8)

Now write code that doesn’t crash. Add safety nets, clarity, and robustness.

#TopicPageTimeLearn
7Type Hints (Advanced)Python-Type-Hints-Advanced2.5hOptional, Union, Callable, mypy validation
8String Formatting & MethodsPython-String-Formatting2hF-strings, parsing CSVs, data validation
9Error Handling & ExceptionsPython-Error-Handling2.5htry/except/finally, custom exceptions, retry logic

Subtotal: ~7 hours (cumulative: ~20 hours)
After TIER 2 you can: Write production-grade functions, validate data, handle failures gracefully, log events.


🏗️ TIER 3: Data Engineering Patterns (Weeks 9-12)

Integrate everything. Build real ETL pipelines and understand distributed computing.

#TopicPageTimeLearn
10OOP: Classes & ObjectsPython-Classes-and-OOP3hDesign patterns, encapsulation, inheritance
11Python for Data EngineeringPython-for-Data-Engineering3hpandas, ETL patterns, PySpark, production practices

Subtotal: ~6 hours (cumulative: ~26 hours)
After TIER 3 you can: Build complete ETL pipelines, understand Airflow operators, scale to Spark.


📊 Learning Path by Goal

Goal: “I just need bootcamp basics”

Follow TIER 1 only (~13 hours)
Time to complete: 2 weeks
Bootcamp readiness: 70%

Goal: “I want to be job-ready”

Follow TIER 1 + TIER 2 (~20 hours)
Time to complete: 1 month
Bootcamp readiness: 90%

Goal: “I want to master data engineering”

Follow TIER 1 + TIER 2 + TIER 3 (~26 hours)
Time to complete: 2 months
Bootcamp readiness: 100% + ahead of class


🗓️ Le Wagon Timeline Alignment

Before Bootcamp Starts (Oct 31, 2026)

MilestoneDateWhat to KnowPages
Complete TIER 1By Aug 31Functions, loops, lists1-6
Complete TIER 2By Sep 30Type hints, error handling7-9
Start TIER 3By Oct 15Basic OOP, pandas intro10-11

During Bootcamp (Nov 2026 - March 2027)

Weeks 1-2:
You already know loops/functions → focus on pandas & SQL joins
Reference: Python-for-Data-Engineering

Weeks 3-4:
Learn Airflow orchestration (builds on classes/OOP)
Reference: Python-Classes-and-OOP

Weeks 5+:
PySpark, distributed processing, production patterns
Reference: Python-for-Data-Engineering (Tier 2: Scaling section)


📝 Study Strategy

Daily Workflow (60 min/day)

Week 1-4 (TIER 1):
├─ 40 min: Read + code examples from page
├─ 15 min: Complete mini-project (if provided)
└─ 5 min: Update your own notes

Week 5-8 (TIER 2):
├─ 30 min: Read advanced concepts
├─ 20 min: Apply to your own code
└─ 10 min: Refactor old projects with new knowledge

Week 9-12 (TIER 3):
├─ 30 min: Read data engineering patterns
├─ 25 min: Build small ETL project
└─ 5 min: Document learnings

How to Use This Roadmap

  1. Start with TIER 1, Page 1 → Read until you understand the concept
  2. Code along → Copy examples, modify them, break them intentionally
  3. Mini-project → If page has one, complete it (weather ETL, etc.)
  4. Link references → Click [[Related]] links when you need context
  5. Consolidate → Review one page per week once you’ve finished TIER 1

🎓 Before You Start: Prerequisites Check

You should be able to answer “yes” to all:

  • Can you write x = 5; print(x) and understand what happens?
  • Do you know what if, for, while keywords do (roughly)?
  • Can you explain what a function is (takes input, returns output)?
  • Are you comfortable with the command line (running python script.py)?

If any are “no”: Spend 2 hours on Codecademy Python basics first, then come back here.


🚨 Common Pitfalls (Don’t Fall Into These!)

PitfallWhy It MattersFix
Skipping TIER 1 basicsYou’ll get confused laterDiscipline yourself to master loops/functions first
Not coding the examplesReading ≠ learning programmingType every code block, modify it, break it
Ignoring type hintsProduction code breaks silentlyType hints catch bugs early (mypy helps)
Not understanding errorsYou’ll waste hours debuggingRead error messages carefully; they tell you what’s wrong
Forgetting try/exceptScripts crash in productionError handling is not optional (see TIER 2)

✅ Consolidation Checklist

After completing each TIER, verify your knowledge:

After TIER 1

  • Write a function that loops through a list and returns transformed results
  • Use list comprehensions instead of loops
  • Explain when to use a while loop vs. a for loop
  • Create a dict, access keys, iterate items
  • Use if/elif/else with and/or operators

After TIER 2

  • Add type hints to your functions (int, str, list[dict])
  • Parse a CSV line into a dict using .split() and .strip()
  • Wrap code in try/except and handle specific exceptions
  • Write a custom exception class
  • Use f-strings with formatting (e.g., f"{value:.2f}")

After TIER 3

  • Design a class with __init__ and methods
  • Create a simple pandas DataFrame from a list of dicts
  • Write a complete ETL function: extract → transform → load
  • Add logging to your pipeline
  • Explain when to use pandas vs. PySpark

📚 Full Page Directory

#TitleDescriptionTimeDifficulty
1Python-Loopsfor/while loops, range(), break/continue2h🟢 Beginner
2Python-Control-Flowif/elif/else, boolean logic, ternary2h🟢 Beginner
3Python-Modules-Functions-ListsModules, functions, lists fundamentals2.5h🟢 Beginner
4Python-List-ComprehensionsPythonic list transformations & filtering2h🟡 Intermediate
5Python-Data-StructuresLists, dicts, sets, tuples—complete guide2h🟡 Intermediate
6Python-Type-Hints-AdvancedOptional, Union, Callable, mypy2.5h🟡 Intermediate
7Python-String-FormattingF-strings, string methods, parsing CSVs2h🟡 Intermediate
8Python-Error-Handlingtry/except/finally, custom exceptions2.5h🟡 Intermediate
9Python-Classes-and-OOPClasses, inheritance, encapsulation3h🔴 Advanced
10Python-for-Data-Engineeringpandas, ETL patterns, PySpark3h🔴 Advanced
11Python-oop-bakery-analogyInteractive OOP tutorial with analogies2h🟡 Intermediate

Total: ~26.5 hours
Recommended pace: 1-2 hours/day over 2-3 months


🔗 Cross-Topic Dependencies

┌─────────────────────────────────────────────┐
│ TIER 1: FUNDAMENTALS                        │
├─────────────────────────────────────────────┤
│ Loops ──┐                                    │
│         ├─→ List Comprehensions              │
│ Control Flow ──→ Loops                       │
│ Functions ─┐                                 │
│            ├─→ Modules (code organization)   │
│ Lists ──────┘                                │
└─────────────────────────────────────────────┘
                    ↓
┌─────────────────────────────────────────────┐
│ TIER 2: PRODUCTION GRADE                    │
├─────────────────────────────────────────────┤
│ Type Hints (improve functions)               │
│ String Methods (parse & validate data)       │
│ Error Handling (robust functions)            │
└─────────────────────────────────────────────┘
                    ↓
┌─────────────────────────────────────────────┐
│ TIER 3: DATA ENGINEERING                    │
├─────────────────────────────────────────────┤
│ Classes/OOP (Airflow operators, later)       │
│ Data Engineering (pandas, ETL, PySpark)      │
└─────────────────────────────────────────────┘

📞 Getting Help

When you’re stuck:

  1. Check the “Related” section at the bottom of each page
  2. Search for keywords in all pages (Obsidian search)
  3. Look at “Tips & Gotchas” — common mistakes are listed
  4. Code it out — don’t just read; type and run examples

🎯 Final Goal

By the end of this roadmap, you’ll be able to:

✅ Write clean, readable, production-grade Python code
✅ Debug errors confidently
✅ Understand and modify real ETL pipelines
✅ Follow Le Wagon bootcamp from Day 1 without feeling lost
✅ Help teammates review their code