@eachrow over a range?

If I do this:

@eachrow df[start:stop, :] ...

It works but the row index always starts from one.
Also @eachrow! doesn't operate on the same df since the indexing copies, and using a view gives error:

dfv = @view df[start:stop, :]
@eachrow! dfv ...
# ERROR: MethodError: no method matching transform!(::SubDataFrame{DataFrame, DataFrames.Index, UnitRange{Int64}})

[pdeffebach]

Can you try that second example on the latest version of DataFrames? 1.3.

I agree there could be some interesting design possibilities here. Check on 1.3 to see where we can start from.

[pdeffebach]

This now works (though it returns the sub-data frame)

julia> df = DataFrame(a = [1, 2, 3, 4]);

julia> dfv = @view df[1:2, :];

julia> @eachrow! dfv begin
           :a = 100
       end
2×1 SubDataFrame
 Row │ a     
     │ Int64 
─────┼───────
   1 │   100
   2 │   100

julia> df
4×1 DataFrame
 Row │ a     
     │ Int64 
─────┼───────
   1 │   100
   2 │   100
   3 │     3
   4 │     4