XML
XPath Basics Selecting Nodes by Path in XML Documents
XPath basics on a small library document: absolute and relative paths, //, *, @ attributes, text(), the parent step and the node-set versus value results.
6 min read
Tag
explainer
59 posts
YAML
Why a Number Turns Into Something Else in YAML Files
Leading zeros, hex, base 60 times and trailing zeros change what a number is. Real output for 0755, 12:30, 1.10 and 1e3, and how to protect values.
5 min read
XML
Pretty Printing XML to Spot Structural Mistakes Quickly
When a minified XML file will not parse, xmllint --format and lxml refuse to indent it. A 30-line tokenizer indents what it can and flags the first mismatch.
6 min read
CSV
Why a CSV Shows Strange Characters Instead of Accents
Seeing odd letter pairs where accents belong means UTF-8 was read as a legacy encoding. See the byte level cause and a table of symptoms.
7 min read
XML
Content Is Not Allowed in Prolog and the Hidden BOM
What Content is not allowed in prolog means in Java: a BOM decoded to text, a double BOM, JSON or text instead of XML, and how to diagnose it.
6 min read
CSV
CSV Line Endings and the CR LF Trap in Shells and Loaders
A CSV from Windows leaves an invisible carriage return on every last column. See it in a shell loop and MySQL, and fix it without damaging quoted fields.
8 min read
YAML
The Norway Problem and YAML Boolean Surprises Explained
Why the country code NO becomes False in YAML 1.1, how keys collide, which parsers are affected and three fixes: quote, use a 1.2 parser or a schema.
5 min read
CSV
How CSV Quoting Works and Why Embedded Commas Break Things
See how a stray comma turns one column into two, what the four quoting states are, and why a backslash does not escape a quote in CSV the way it does in code.
8 min read
CSV
What RFC 4180 Says and Does Not Say About CSV Files
RFC 4180 is a four page memo, not a standard. Read its seven rules, the grammar quirks that surprise people, and how real files and readers drift from it.
10 min read
YAMLGuide
YAML Syntax You Need to Stop Guessing At and Start Knowing
A complete guide to everyday YAML syntax: indentation, scalars, quoting, collections, block strings, anchors, null and versions, tested with real parsers.
19 min read
Editor's pick
CSVGuide
Everything a CSV File Does and Does Not Promise You
A CSV file promises rows and delimiters and little else. See what six readers did with one awkward file, and how to read CSV without guessing.
24 min read