XMLGuide
XSLT and XQuery for Real Transformations Step by Step
A working guide to XSLT 1.0, 3.0 and XQuery on the same files: templates, grouping, enrichment, JSON output, parameters, debugging, speed and which to pick.
19 min read
Library
Everything you need to level up your coding skills.
Excel
Why Excel Is Slow With Formulas Over Many Rows Explained
Why Excel slows down with many formulas: the calculation chain, volatile functions, whole column references and scanning lookups, and how to find the cost.
8 min read
PostgreSQL
How to Read a PostgreSQL Query Plan Step by Step Guide
Read a PostgreSQL query plan line by line: tree shape, estimate and actual groups, loops, own time per node, and a worked plan with one slow step.
7 min read
Editor's pick
CSVGuide
Working With CSV Files in the Shell Without Opening Excel
A practical guide to CSV in the shell: coreutils, awk, csvkit, Miller, qsv and DuckDB compared on 2,000,000 rows, with the quoting rule and a triage script.
22 min read
Excel
Reading a 500 MB Excel File Without Running Out of Memory
Read a very large xlsx in Python without exhausting memory: why xlsx expands, openpyxl read only mode, calamine and DuckDB, and how to measure peak memory.
7 min read
JSON
Querying JSON Text With json_extract in SQLite Step by Step
What json_extract returns for each JSON type in SQLite, how paths and multiple paths behave, the number and text traps, and what repeated calls cost.
7 min read
CSV
Python CSV Newlines and the Blank Line Bug on Windows
Why a CSV written by Python shows a blank line after every row on Windows, how newline='' prevents it, and how to check the bytes. Reproduced without Windows.
8 min read
XMLGuide
Parsing XML in Java C Sharp and Other Typed Languages
One XML file and one task in eight languages, with each output, the defaults that change your data, and how each treats absent, empty and bad values.
17 min read
YAMLGuide
Using YAML With Databases for Seeds Exports and Queries
Five jobs YAML does next to a database: seed data, exports, stored documents, test fixtures and queries, with tested code for PostgreSQL, SQLite and DuckDB.
19 min read
ExcelGuide
A Guide to Excel Files That Are Too Big or Too Slow
Diagnose an Excel workbook that is huge, slow to calculate or too large to read in code, then fix it by size, formulas, the Data Model or a different format.
17 min read
CSV
Python CSV Error Field Larger Than Field Limit and the Fix
Fix _csv.Error field larger than field limit (131072). Tell a genuinely large cell from an unclosed quote, raise the limit safely and find the bad record.
8 min read
XMLGuide
Handy Command Line Tools for XML Work in Daily Practice
The command-line tools that cover daily XML work: xmllint, xmlstarlet, xsltproc, xq and yq, with tested commands, timings, exit codes and the traps of each.
19 min read
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