Sorting a DataFrame

[Eddy_Offermann]

Would it be possible to sort a DataFrame using a particular column ?

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ROOT Version: Not Provided
Platform: Not Provided
Compiler: Not Provided

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[Danilo]

Hi Eddy,

this is presently not possible. We will introduce this capability for cached datasets only, i.e. in memory, for 6.18.
From your expert perspective, how would you see this interface? Would a sorting upon caching enough or you would need to re-sort at any point in time?

mySortedImmutableRdf = myRdf.Cache("", {"sortCol1", "sortCol2"});
// or 
mySortableRdf = myRdf.Cache();
ROOT::RDF::Sort(mySortableRdf, {"sortCol1", "sortCol2"});

Cheers,
Danilo

[Eddy_Offermann]

Hi Danillo,

For my use case only one sort would be done . Just so that I understand the
interface. I would like to sort the rows of a RDataFrame by using “sortCol1” as major index and possible “sortCol2” as minor index.

I would prefer option 2 just to separate aching and sorting.

Best Eddy