CSV Guides
Practical, step-by-step guides for cleaning, converting, merging, and securing CSV data, written from real workflows, not marketing copy.
Looking for a quick definition instead? See the CSV and data glossary.
CSV Best Practices: A Professional Guide
Encoding, headers, delimiters, dates, and the standards that keep CSV files reliable.
How to Clean a CSV File: A Step-by-Step Guide
A repeatable process for turning a messy export into analysis-ready data.
CSV vs Excel vs JSON: Which Format Should You Use?
When to use each format, and how to convert between them without losing data.
How to Merge CSV Files Without Losing Data
Merging vs. combining, join types, and the mistakes that silently drop rows.
How to Convert a CSV File to Excel (XLSX)
Three methods, and the leading-zero and date pitfalls that silently corrupt data.
How to Convert a VCF File to CSV (Export Contacts)
Export a vCard from your phone or account, then convert it without losing extra phones and emails.
How to Compress a CSV File (Reduce File Size)
Lossless ZIP compression versus genuinely shrinking the data, and when to use each.
CSV Encoding Issues Explained (and How to Fix Them)
Why files show garbled characters, and how to fix encoding problems for good.
How to Remove Duplicate Rows from a CSV File
Exact vs. fuzzy deduplication, and choosing the right key columns.
Pivot Tables for CSV Data: A Practical Guide
How pivot tables work, and when to use one instead of a simple group-by.
CSV File Security and Privacy: What You Need to Know
Client-side vs. server-side processing, and anonymizing data before you share it.
Importing CSV Into a Database: A Practical Checklist
Catching silent type coercion and truncation before they reach production.
Working With Large CSV Files Without Crashing Excel
Why spreadsheets struggle at scale, and what to do instead.
How to Split a Large CSV File Into Smaller Files
Splitting strategies, and how to keep the pieces recombinable.
CSV Date Formatting: How to Fix Ambiguous Dates
Why dates break across regions and tools, and the ISO 8601 fix.
How to Detect Outliers in a CSV Dataset
IQR vs. z-score, and why an outlier isn't automatically an error.
Exploratory Data Analysis (EDA) for Beginners
A practical checklist to run on any new dataset before you trust it.
How to Anonymize CSV Data Before Sharing It
Masking, pseudonymization, and the quasi-identifier problem.
Using Regex to Extract Data from a CSV Column
A practical introduction to regex for structured text extraction.
How to Validate CSV Data Before It Reaches Production
Range, format, and referential checks, and why to report not just reject.
CSV vs Parquet: When to Switch to Columnar Storage
When Parquet's performance advantages are worth the tradeoff.
Common CSV Import Errors and How to Fix Them
A troubleshooting reference for the most frequent import failures.
Building a Repeatable CSV Reporting Workflow
Clean, aggregate, visualize, export, in a consistent order every time.
How to Clean CSV Exports for Tax Reporting
Turn raw QuickBooks, Stripe, PayPal, and bank exports into reconcilable data before you file.
Fixing Shopify CSV Errors Before Black Friday
The product and inventory CSV errors that break bulk imports, and how to fix them before BFCM.
Year-End Data Cleanup: Deduplicate Your CRM and Contact Lists
Merge duplicate contacts, standardize fields, and archive dead records for a clean new year.
Back-to-School CSV Prep: Importing Student and Staff Rosters
Validate and clean roster CSVs before the first week so the SIS or HR import just works.
How to Export Spotify Playlists to CSV
Get your playlists into a CSV, then chart them by artist, decade, and tempo.
Explore Steam and FIFA Datasets Without Python
Filter, aggregate, run SQL, and chart big game datasets in the browser, no pandas.
Managing Personal Finance CSVs from YNAB and Notion
Merge monthly budget exports, fix categories and dates, and chart your spending privately.
How to Analyze Your Letterboxd and Goodreads CSV Exports
Build your own year in review: ratings, pace, favorite decades, directors, and authors.
Sample data to practise with
Free, realistic CSV, TSV and JSON datasets — plus deliberately dirty files for cleaning practice. Browse all sample files →
Sample CSV with headers
A clean, well-formed 100-row baseline file for a first import test.
Sample dirty CSV
Mixed casing, whitespace, five date formats, duplicates — made for cleaning tutorials.
Large sample CSV (12,000 rows)
About 1 MB of transactions for performance and pagination testing.
Interactive data stories
Explorable pages built from public open data.
The AI Data Center Power Map
Interactive US map of data-center build-out, projected grid demand growth, and electricity prices by state. EIA, EPA and Global Energy Monitor data, CSV download.
The Real Cost of AI
Source-linked infographic: electricity per AI query, energy to train a frontier model, and data centers as a share of the grid.