XML
Indexing XML Columns in PostgreSQL Without Wrecking Inserts
An expression index on xpath turned a 245 ms scan into 1 ms on 50,000 documents and made loading 2.8 times slower. A generated column does the same.
6 min read
Library
Everything you need to level up your coding skills.
JSON
Reading JSON From an API With requests and Handling Errors
response.json() raised JSONDecodeError for an empty body, a 204, an HTML 502 and a BOM. Check status first, set a timeout and retry with a Session, as tested.
8 min read
CSV
Checking Row and Column Counts of a CSV Before Loading
How many rows does this CSV have? wc -l, awk, csv, pandas and DuckDB gave 7, 8, 7, an error, 4 and 8 on one small file. Count records and field widths.
10 min read
Excel
Converting Excel to Markdown and HTML Tables for Docs
Turn a worksheet into a Markdown or HTML table for documentation with pandas, escape pipes and line breaks, align numbers and keep wide tables readable.
6 min read
CSVGuide
How to Validate a CSV File Before You Trust the Data
Validate a CSV delivery in five layers, bytes, structure, schema, values and keys, with line numbers and exit codes: 193,708 rows checked in about a second.
21 min read
XML
Streaming XML Into PostgreSQL Without a DOM Using COPY
Parse a 127 MB XML file with iterparse and feed two tables through COPY. 400,000 orders loaded in 6.5 seconds and 44 MB, against 38 seconds for row inserts.
6 min read
YAML
Helm Values Files Without Copy Paste Using Layered Values
Layer Helm values so production overrides only what differs: maps merge, lists replace, --set wins. Rendered with helm template and checked with kubeconform.
7 min read
Excel
Converting Excel to SQL Insert Statements Safely and Fast
Turn a worksheet into SQL INSERT statements that quote text, handle NULLs and dates, and load in batches, or skip the script and use COPY or a driver.
6 min read
JSON
Faster JSON in Python With orjson and What Changes
orjson wrote a 35 MB document 6 times faster than json and parsed it 1.7 times faster. What it returns, what it rejects and what to check before migrating.
6 min read
CSV
Finding Rows That Do Not Match the Expected Pattern in a CSV
Check every column of a CSV against a regex and report failing rows with file line numbers. fullmatch beats match, and 2025-13-45 passes a date pattern.
9 min read
XML
Benchmarking ElementTree lxml and iterparse on 127 MB
Four ways to sum 1.2 million order lines from a 127 MB XML file, with time and peak memory, plus the clearing pattern that keeps streaming flat.
6 min read
Excel
Converting Excel to Parquet for Faster Analytics Loads
Convert an Excel workbook to Parquet with pandas or DuckDB, fix column types first, write one file per sheet and check counts so analytics loads run fast.
7 min read
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