XML
XML Attributes Versus Child Elements and How to Choose
Attributes or child elements for the same 50,000 orders: size, gzip, parse time, newline handling, JSON conversion and the rules that decide which to use.
6 min read
Library
Everything you need to level up your coding skills.
Excel
An XLSX File Is a Zip of XML and Here Is What Is Inside
Unzip an XLSX workbook, read its sheet XML and shared strings by hand, then write a 30 line Python reader that rebuilds the table without any Excel library.
8 min read
JSON
Why JSON Has No Comments and What People Do Instead
JSON has no comment syntax by design, so a // note fails in every parser tested. What people do instead: _comment keys, $comment, JSONC, JSON5 and YAML.
6 min read
Editor's pick
CSVGuide
Handling CSV Files Too Big to Open in Excel or Python
A decision guide for CSV files too big to open: look, count, sample, query in place, chunk, split, compress or convert, with numbers from a 1.3 GB file.
17 min read
XML
Well Formed Versus Valid XML and the Difference in Practice
Well formed means the syntax parses, valid means it follows a DTD or XSD. Ten broken files and two schemas run through xmllint show what each catches.
6 min read
Excel
XLS Versus XLSX Versus XLSB and Which to Hand Over
Compare the XLS, XLSX and XLSB Excel formats on limits, size, macros and library support, detect which one a file really is, and pick one to hand over.
8 min read
JSON
JSON Data Types and What Is Missing From Them Entirely
JSON has six value types and no date, binary, integer, decimal, set or undefined. See what Python and JavaScript do to each missing type when they serialize.
6 min read
CSV
Converting a CSV to Parquet and Why You Might Want To
One DuckDB statement turned a 130 MB CSV into a 34 MB Parquet file; typed columns, dictionary encoding and min/max statistics explain the faster queries.
10 min read
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
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
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
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
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