CSV
A Government Dataset With Footnotes in the Data Cells
Statistical CSVs put flags in value cells: 1,204,300 (p), 5.3 e, and dots for missing. Split number from flag, keep both and check against the stated total.
7 min read
Library
Everything you need to level up your coding skills.
CSV
A Log Export With Unescaped Quotes and How to Read It
A log export has quotes inside quoted fields without doubling them. See what Python and DuckDB return, which setting reads them right and how to prove it.
7 min read
CSV
A Supplier Price List With Merged Header Rows Fixed
A price list CSV has title lines, a header on row 4, category names written once per group and a footer. Skip, forward fill, filter and check the item count.
7 min read
CSV
An Analytics Export With Percent Signs and Dashes Cleaned
An analytics CSV writes numbers as text: 12,430, 42.5%, $1,204.50, (4.1%) and dashes. Convert them with one macro and prove nothing is left unparsed.
6 min read
CSV
A CRM Export With Multi Line Notes and How to Parse It
A CRM export has notes with line breaks inside quoted fields, so line counts and grep mislead. Parse by records, then flatten the breaks or keep them.
6 min read
CSV
An Ecommerce Export With Commas Inside Product Names
A product export writes names with commas and no quotes, so rows have 6 fields, not 4. Rejoin the middle fields from the good ends and verify every row.
6 min read
CSV
A Bank CSV With Dates in Two Formats and How to Fix It
A statement mixes 2026-03-04 and 05/03/2026 in one column. Classify each row, prove the slash order from the data, convert, and check the dates are in order.
6 min read
PostgreSQL
Storing Uploaded Excel Files and Their Parsed Rows
Store uploaded Excel files and their parsed rows in PostgreSQL: keep the original, stage, track errors, dedupe by hash and link rows to uploads.
7 min read
PostgreSQL
Reading XML With xmltable in a Real Import in PostgreSQL
Import XML into PostgreSQL with xmltable: XPath row and column paths, namespaces, attributes, nested elements, large files and validation of a feed.
6 min read
Excel
Error Handling With IFERROR and Safer Alternatives Today
Handle Excel formula errors without hiding bugs: IFERROR versus IFNA, testing inputs first, ISERROR functions, XLOOKUP not-found values and error codes.
6 min read
Excel
SUMPRODUCT as a Swiss Army Formula for Conditional Sums
Use SUMPRODUCT for weighted averages, OR conditions, multi-column counts and arithmetic before summing, with its speed limits and what to use instead.
6 min read
XML
Dealing With XML Feeds That Break Their Own Schema
A feed with a raw ampersand, a missing id, a bad date, a duplicate id and an extra element: repair what is safe, quarantine the rest, report each reject.
7 min read
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