YAML
Environment Variable Substitution in YAML Config Files
Substitute environment variables into YAML config after parsing, not before. Expanding text first broke on a colon and hash; a typed walk kept the value.
6 min read
Library
Everything you need to level up your coding skills.
MySQL
Running MySQL in Docker With a Data Volume That Persists
Run MySQL 8.4 in Docker with a named volume, environment variables, a custom config, health checks, initialization scripts and safe upgrades.
6 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
PostgreSQL
Creating Your First Database User and Schema in PostgreSQL
Create your first PostgreSQL role, database and schema: CREATE ROLE with LOGIN, a database with an owner, search_path, and the public schema change.
7 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
YAML
Reading YAML Front Matter From Markdown Files in Python
Split a Markdown file into YAML metadata and body with one regex, then handle dates, CRLF, a BOM, a missing closing line and body text with dashes.
6 min read
MySQL
Installing MySQL 8.4 on macOS Linux and Windows Step by Step
Install MySQL 8.4 LTS on macOS, Ubuntu and Windows: package sources, first start, the root account, secure setup and checks that the server works.
6 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
PostgreSQL
Running PostgreSQL in Docker With a Persistent Volume
Run PostgreSQL in Docker with a named volume so data survives restarts, set the password and database on first start, publish the port safely and use Compose.
7 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
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