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setnames for lists? #1948
Description
Is there a reason usage of setnames is restricted to data.table and data.frame?
Seems inconsistent that rbindlist can take list/data.table/data.frame as input and return the correct data.table as output; why not setnames?
This would have the advantage over setNames of being done by reference (usually minor for this particular operation) as well as allowing for more consistency in how I use data.table functions in my code...
Activity
mattdowle commentedon Dec 2, 2016
Originally I seem to remember that
setnamesjust worked ondata.table. To restrict todata.tablewhat you could do by reference to avoid unexpected breakage ifset*could reach outsidedata.table's remit.Say a package imports
data.tableand usessetnameson the input it is passed from a user. If that package doesn't remember it should not callsetnameson adata.frameinput, the user using that package could end up with a changed-by-referencedata.frame.But
data.tableusers in their own code really wanted to callsetnamesondata.framesince they wanted to be trusted, keeping thedata.frameas adata.frame, rather than converting to adata.table. So we yielded and crossed our fingers. Relaxing to allow it onlisttoo is one step further.Are we sure we don't have any problems in packages importing
data.table, callingset*ondata.frameinputs? Let alonelistyet.MichaelChirico commentedon Dec 2, 2016
MichaelChirico commentedon Jul 8, 2025
I don't think this is a real concern.