Number groups in dataframe

Specific Domains Data
,
7

Two things

  1. You can use the functions with Chain.jl. Chain.jl and DataFramesMeta.jl macros are not tied together in any way.
julia> df_new = @chain df begin
           groupby(_, :g)
           transform(groupindices => :gnum)
       end
6×3 DataFrame
 Row │ x          g       gnum  
     │ Float64    String  Int64 
─────┼──────────────────────────
   1 │ 0.465506   c           1
   2 │ 0.0945491  c           1
   3 │ 0.512721   a           2
   4 │ 0.444936   b           3
   5 │ 0.631455   b           3
   6 │ 0.667982   b           3

But also, you can use it with @transform as follows

julia> df_new = @chain df begin
           groupby(_, :g)
           @transform :gnum = $groupindices
       end
6×3 DataFrame
 Row │ x          g       gnum  
     │ Float64    String  Int64 
─────┼──────────────────────────
   1 │ 0.465506   c           1
   2 │ 0.0945491  c           1
   3 │ 0.512721   a           2
   4 │ 0.444936   b           3
   5 │ 0.631455   b           3
   6 │ 0.667982   b           3