Feature Request: functions (sum avg, min max, free definable) in addition to count

[Mirage10]

Frequency Tables are very powerfull tool - a very good concept by the way.
This feature request addresses more flexibility. The cells are currently doing counting only. It would be very helpful to handover a specific function, so that the cells are not providing counts, instead they are providing function value based on the dadasets involved.

[nalimilan]

Actually, that was my original idea when the package was called Tables.jl, but I never worked on it. At this point, though, much code would be duplicated with DataFrames.jl/DataFramesMeta.jl (JuliaData/DataFrames.jl#894). We should find a way to share code.

@tshort Any ideas about this?

[tshort]

Sharing code is a good idea. The differences between DataFrames/DataFramesMeta and FreqTable are mainly different API to do similar things.