Excel
Designing Database Tables From a Messy Excel Sheet
Turn a wide Excel sheet into database tables: find the entities, choose keys, remove repeated groups and derived columns, and check the design with queries.
8 min read
Library
Everything you need to level up your coding skills.
Excel
Moving From Excel to PostgreSQL Step by Step Without Loss
Move an Excel workbook into PostgreSQL: staging table, clean, normalized tables, constraints, roles, a verified load, and Excel as the read connection.
7 min read
Excel
Moving From Excel to SQLite for a Small Team Step by Step
Move an Excel list into SQLite: clean it, design tables, load with Python, add constraints, query from Excel and know the limits for a small team.
7 min read
Excel
Ten Signs Your Excel File Needs to Become a Database
Ten concrete signs that an Excel file has become a database, from several editors to lost updates and broken lookups, with a quick test for each.
7 min read
ExcelGuide
When a Spreadsheet Has Become a Database and What to Do
How to tell that an Excel file now behaves as a database, choose SQLite, Access or PostgreSQL, design tables, migrate safely and keep Excel as a reader.
17 min read
Excel
Testing That a Generated Excel Report Is Actually Correct
Test a generated Excel report with pytest: structure, control totals, formulas, formats and edge cases, plus a fixture of bad input and a golden file.
8 min read
YAML
Round Tripping YAML Without Losing Comments or Order
Edit a YAML file in code and keep its comments, anchors and quotes. PyYAML drops them, ruamel.yaml and yq keep them, and each changes some whitespace.
6 min read
YAML
YAML Anchors Aliases and Merge Keys Without Surprises
Define a block once with an anchor, reuse it with an alias, and merge it with the merge key. Real output shows overrides, sharing and where merging stops.
5 min read
YAML
YAML Lists and Mappings Without Confusion in Real Files
Block and flow styles for sequences and mappings, lists of mappings, empty collections and why a missing value is None, each with its parsed result.
6 min read
YAML
YAML Multiline Strings With Pipe and Greater Than Signs
The pipe keeps line breaks, the greater than sign folds them, and chomping indicators control the final newline. Six variants and the exact strings.
5 min read
YAML
YAML Strings Quoting and When You Really Need Quotes
Plain, single quoted and double quoted YAML strings compared, with the characters that force quotes and a table of values that silently change type.
5 min read
YAML
YAML Indentation Rules and Why Tabs Break Everything
How YAML uses spaces to build structure, why a tab is rejected, and how one extra space turns a sibling into a child. Real parser output for each case.
6 min read
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