[RDataFrame] Expose more local df operations for distributed RDF #15039
Description
Explain what you would like to see improved and how.
There are many useful operations such as GetColumnType that is trivial to be included in the operation list of distributed RDF. I suggest to expose these operations to users.
The GetColumnType method is useful when someone tries to save columns based on the column type, e.g. I only want to save columns that are standard supported types for numpy arrays when I try to do AsNumpy.
The very easy way to implement this would be to add it similar to how GetColumnNames is added here.
A workaround for now would be to do
rdf._headnode._localdf.GetColumnType
ROOT version
6.30/04
Installation method
LCG (Swan)
Operating system
Linux
Additional context
No response