XMLGuide
What XML Is Good At and Why It Still Shows Up in Your Data
A tested beginner guide to XML: where you will meet it in data work, what it does better than JSON, how it is structured, and the first checks to run.
17 min read
Library
Everything you need to level up your coding skills.
ExcelGuide
What Is Inside an Excel File and What It Means for Data
See what an XLSX workbook really contains, from cell types and shared strings to dates, formulas, styles and limits, and what each part means for your data.
17 min read
YAML
Merging Two YAML Files in Python With a Deep Merge
dict update is shallow and replaces whole blocks. A 10-line deep merge, the list policy choice and what null means, tested on a base and an override file.
6 min read
MySQLGuide
Getting a MySQL Server Running and Usable From Scratch
A beginner guide to getting a MySQL server running: choose a version, install, secure, connect, create users and fix the first errors.
16 min read
JSONGuide
What JSON Allows and What Parsers Quietly Accept in Practice
The JSON grammar fits on a page, and parsers still disagree on trailing commas, NaN, duplicate keys, big numbers and more. A 26-case test across five parsers.
17 min read
CSV
Round Tripping Exports Back Into Imports Without Drift
A CSV export should re-import to the same data. A test where identical files hid a NULL turned into an empty string, and how to test round trips on rows.
7 min read
PostgreSQL
Installing PostgreSQL on macOS Linux and Windows Today
Install PostgreSQL on macOS with Homebrew, on Linux with packages and on Windows with the installer, then check that the service runs.
7 min read
Excel
Locking Down Shared Input Sheets Without Breaking Them
Lock a shared Excel input sheet so people can enter data but not break it: protect the sheet, allow the right actions, handle tables, keep a master.
8 min read
Excel
Checking an Incoming Workbook Against a Template by Code
Check an incoming Excel workbook against a template in Python: headers, column types, required cells, allowed values, duplicates and a clear report.
9 min read
Excel
Spotting Data Entry Errors With Conditional Formatting
Use Excel conditional formatting to flag duplicates, blanks, out of range values, bad dates and unknown codes as people type, with formulas that stay fast.
7 min read
Excel
Using Excel Tables for Structured Input in Data Entry
Use Excel tables for data entry: automatic expansion, calculated columns, structured references, validation that follows new rows, and reading tables by name.
7 min read
Excel
Protecting Formula Cells From Edits in Shared Workbooks
Protect Excel formula cells from accidental edits: lock cells, protect the sheet, allow sorting and filters, hide formulas, and set it up from code.
7 min read
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