API: concatting DataFrames does not skip empty objects by jorisvandenbossche · Pull Request #39035 · pandas-dev/pandas (original) (raw)
See discussion in #38843
To repeat the main argument: when not skipping empty objects, the resulting dtype of a concat-operation only depends on the input dtypes, and not on the exact content (the exact values, how many values (shape)). In general we want to get rid of value-dependent behaviour. In the past we discussed this in the context of the certain values (eg presence of NaNs or not), but I think also the shape should not matter (eg when slicing dataframes before contatting, you can get empties or not depending on values).
This starts with reverting the change for DataFrame. If we opt for this behaviour, in addition we should also discuss how to change the Series behaviour.