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
Topic
CSV
The format everyone exports and nobody specifies. Delimiters, quoting, encodings and loading it into a database intact.
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
CSVGuide
Worked CSV Problems and the Patterns Behind Them Explained
Eight messy CSV files solved end to end with a check each: mixed dates, unquoted commas, multi-line notes, display formats, headers, bad quotes, footnotes.
18 min read
CSV
Reconciling a Bank Statement CSV With Your Ledger in SQL
Match a bank statement CSV against a ledger in SQL with a date tolerance, pair duplicate amounts correctly, and explain the difference in totals row by row.
7 min read
CSV
Making Quick Charts From a CSV With Python and DuckDB
Make quick charts from a large CSV: aggregate in DuckDB, plot with matplotlib or draw text bars in the terminal, and keep the charts honest.
6 min read
CSV
Checking if a CSV Column Is Normally Distributed With Python
Test whether a CSV column follows a normal distribution using skew, kurtosis, percentiles and Shapiro-Wilk, and why a huge file always fails the test.
7 min read
CSV
Sampling a CSV for a Fast First Look at Large Data
Sample a large CSV for a quick first look: why the top rows mislead, random and reproducible sampling in DuckDB, and how the error shrinks with sample size.
6 min read
CSV
Finding the Top Customers by Revenue in a CSV File
Rank customers by revenue in a CSV with SQL, compute cumulative share and the top 10 percent, handle ties and refunds, and read the concentration curve.
7 min read
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