Nikita Klimenko

Hi! Can you provide a screenshot of the desired table and what you get with `pivot { col1 then col2 } .groupBy { row1 and row2 }`? What i see...

Thank you for the use case, it's very interesting! Maybe `df.pivot { Gender then Party }.groupBy { Province }.sum { Age }` does the thing? It yields a dataframe with...

Now that you mention horizontal / vertical grouping, documentation states https://kotlin.github.io/dataframe/pivot.html ``` df.pivot { pivotColumns }.groupBy { indexColumns } pivotColumns — columns with values for horizontal data grouping and generation...

I see the problem, yes. Can you provide the dataset so i can give it a try myself? It would be easier for me to figure it out in REPL...

> Also I want to make saving to Arrow with some pre-defined schema and print warnings (or throw exceptions in strict mode) if some column does not exist in actual...

> > Sounds like AnyFrame.convertTo > > Does it sound good? Saving "as is" wold be default behavior but since Arrow supports explicit schemas, I want to use them also....

Regarding logging / throwing exceptions, maybe some kind of a callback parameter could help? Like `df.arrowWriter(..., SchemaMissmatch.Ignore / SchemaMissmatch.Throw / SchemaMissmatch.Callback { // log here })` `SchemaMissmatch.Ignore` and `SchemaMissmatch.Throw` are...

> Returning to the issue topic, what do you think about addition dataframe feedback generally? I'm concerned that logging could be a slippery slope. If a library starts to produce...

Hi! Thank you for the report and pointing that 'assert' is turned off by default.

Hi! It should now throw an exception on `0.9.0-dev-1079