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
Library
Everything you need to level up your coding skills.
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
JSON
Repairing Truncated JSON From a Cut Off Response or File
A response or file that stops mid-document fails with an end-of-input error. How to confirm truncation, salvage complete records and decide on repair.
8 min read
CSV
Checking a CSV for Invalid UTF8 Before You Load It
Find the lines and bytes that break a UTF-8 load with iconv, isutf8, grep or a short Python script, and see how PostgreSQL and DuckDB report them.
7 min read
Excel
Exporting MySQL Data to Excel With a Python Script
Export a MySQL query to a clean XLSX with PyMySQL and pandas, handling DECIMAL, zero dates, tinyint flags and utf8mb4, and compare it with Workbench.
7 min read
XMLGuide
XPath Queries That Cover Most Real Needs in XML Work
A tested XPath guide: the twenty expressions that cover most needs, the traps (namespaces, positions, units, injection), tools, timings on 200,000 records.
18 min read
CSV
Handling Emoji in CSV Imports Without Losing Characters
MySQL utf8 columns hold three bytes per character, so an emoji becomes a question mark during a CSV load with only a warning. See the fix and the checks.
7 min read
Excel
Exporting SQL Server Query Output to an Excel File
Export SQL Server query results to XLSX with pyodbc and pandas, and see what SSMS, bcp and the Import and Export Wizard give you instead.
7 min read
JSON
Fixing JSON With Unescaped Newlines in Strings Safely
A raw newline, tab or backslash inside a JSON string is invalid. See the errors Python and Node give, how strict=False helps and how to write strings safely.
8 min read
CSV
Why Your CSV Has Question Marks Where Names Should Be
Question marks in a CSV are lost data, not a display bug. See where the substitution happens, count the damage and decide whether the export is broken.
7 min read
YAML
YAML Error Could Not Find Expected Colon and Its Causes
A line with a word and no colon makes the parser fail while scanning a simple key. See the message in three parsers, the usual causes and the fixes.
6 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
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