XML
XML Versus JSON Versus YAML for Configuration Files
One small config written three ways: size, comments, types and the YAML country code that parses as False. A decision guide for choosing between them.
5 min read
Library
Everything you need to level up your coding skills.
CSV
Checking That Every Date in a CSV File Parses Correctly
Check every date in a CSV with a strict parse and a round trip, then ranges. strptime accepted 2025-3-4, DuckDB cast kept the date of 2025-03-14 10:30.
10 min read
Excel
Designing a Report Query Before Touching Excel at All
Design a report query before opening Excel: fix the grain, avoid join fan-out, put rules in SQL, bind parameters and test totals against a trusted number.
8 min read
PostgreSQL
Reading BUFFERS Output in EXPLAIN for PostgreSQL Queries
Read the BUFFERS output in PostgreSQL EXPLAIN: shared hit, read, dirtied and written, temp blocks, I/O timing, and what the numbers say about cache and disk.
7 min read
CSV
Finding Duplicate Keys in a CSV File Before an Import
Find repeated ids in a CSV before a primary key rejects the load, with SQL, pandas and uniq -d, line numbers and an exact versus conflicting split.
9 min read
XMLGuide
Choosing XML Over the Alternatives or Not for a New Project
A decision guide for XML versus JSON, YAML, CSV and Protocol Buffers, with measured sizes and parse times, six scenarios and a migration path.
16 min read
JSONGuide
JSON in JavaScript and Node Done Carefully and Correctly
A tested guide to JSON in JavaScript and Node 24: what stringify drops, parse errors, big numbers, dates, circular data, cloning, files and large inputs.
20 min read
ExcelGuide
Building Excel Reports From SQL Queries People Trust
Build Excel reports from SQL that readers trust: design the query, write sheets, formats and charts from code, check totals, version the query, schedule it.
18 min read
CSV
Validating CSV Columns With Python and pydantic Models
Validate each CSV row against a pydantic model with types, literals, patterns and a cross-field rule: 193,708 rows in 0.95 s, with file line numbers.
10 min read
YAML
Reading YAML Anchors in CI Files and Merge Key Gotchas
How to expand anchors and merge keys in CI files to see the effective job, and the yq 4.54.1 merge-key order bug that gave retries 2 where the spec says 5.
6 min read
CSV
Writing a Schema for a CSV With Frictionless Data in Python
Infer a Table Schema, fix it by hand, add unique, enum and pattern constraints and validate with Frictionless: 10 errors for 8 faults in 193,708 rows.
11 min read
Excel
Converting Google Sheets to CSV or Excel With a Script
Export a Google Sheet to CSV or xlsx from a script using the export URL, the Drive API or gspread, choose the sheet by gid and handle sharing and auth safely.
6 min read
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