Phase 0: Working with Data in Python · ~30 minutes · Python

Data Without a Library

A CSV file is just text with a convention. The convention has an edge case, and that edge case will corrupt your data silently if you hand-roll the parsing yourself.

Hiring signal: Understands what a CSV parser actually has to handle (quoting, embedded delimiters) instead of treating file-reading as a solved, invisible detail

What you will learn

Parse a CSV file by hand into a list of dicts using only core Python
Explain why splitting on a delimiter character breaks when a field's own content contains that character
Diagnose a silent data-misalignment bug caused by naive comma-splitting
Recognize why real CSV parsing needs a quoting convention, not just a split() call

Introduction

Type: Learn Languages: Python Prerequisites: None — Course 01 (Programming & CS Foundations) skills only Time: ~30 minutes

Objective

Learning objectives

Parse a CSV file by hand into a list of dicts using only core Python
Explain why splitting on a delimiter character breaks when a field's own content contains that character
Diagnose a silent data-misalignment bug caused by naive comma-splitting
Recognize why real CSV parsing needs a quoting convention, not just a split() call

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You've read the first 2 sections. The rest of this lesson covers The Problem, The Concept, Build, Key Terms & Next — plus a hands-on lab, quiz, and project artifact.

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