XMLGuide
Handling XML in Warehouses and Lakes the Practical Way
How to get XML into Snowflake, BigQuery, Spark, DuckDB and a lake: keep raw files, parse once with a typed schema, store Parquet and reconcile counts.
16 min read
Library
Everything you need to level up your coding skills.
YAMLGuide
Choosing YAML TOML JSON or INI for Config Without Regret
Pick a config format by who edits it and what reads it. One config tested in YAML, TOML, JSON, INI and more: types, traps, errors, size and switching cost.
17 min read
Excel
Producing a Monthly Management Pack From SQL Queries
Produce a monthly management pack from SQL: fixed sheets, prior month and budget comparisons, checks that tie out, and a scheduled build with sign off.
8 min read
CSV
Testing a CSV Export for Truncated Last Lines in Python
A cut-off CSV loaded in pandas without a warning, last row 200000,Ana,Smith,...,2. Check the final byte, the last record's width, quotes, row count and gzip.
11 min read
JSONGuide
Using jq to Slice Up JSON in the Terminal Reliably
A tested guide to jq 1.8 for slicing JSON in the terminal: filters, streams, CSV, grouping, logs, safe variables, in-place edits and number quirks.
17 min read
XML
XML Versus CSV for Exchanging Tabular Data Between Systems
A partner asks for XML for a flat table. Measured on 100,000 rows, XML was 2.7 times the CSV size, though gzip nearly erased the gap. When each is right.
6 min read
Excel
Writing Conditional Formatting From Code in Workbooks
Write Excel conditional formatting from Python with XlsxWriter or openpyxl: value rules, color scales, data bars and formula rules, with tests.
7 min read
CSV
Detecting Columns That Changed Type Between CSV Deliveries
April's load failed on qty 1.5, but six columns had drifted. Compare per-column kinds of value between two CSV deliveries, not just inferred types.
11 min read
CSV
Validating a CSV File Against a Lookup Table With SQL
Find CSV values missing from a lookup table with an anti-join, keep line numbers right, avoid the NOT IN trap with NULLs and see a foreign key's error.
10 min read
YAMLGuide
Parsing YAML in Languages Other Than Python Compared
One YAML document parsed in Node, Go, Java, Ruby, PHP, Rust, C# and yq: types, dates, duplicate keys, strict modes, safety and parse speed, all measured.
17 min read
Excel
Sending Charts From a Query to an Excel Sheet by Script
Send charts from a SQL query to an Excel sheet by script: write the data, add a native chart with XlsxWriter or openpyxl, size it and label it.
7 min read
JSON
JSON parse and stringify Options You Probably Missed
The extra arguments of JSON.stringify and JSON.parse, tested in Node 24: toJSON, replacer arrays, indent limits, call order and exact numbers.
9 min read
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