Difference result between insertcols! and transform! in spreading one column to many columns

Specific Domains Data
1

I tried to understand how this script here works and I tried to reproduce it in other ways:

this with insertcols! it seems to work

     df=DataFrame(name=["James Smith 39","Michel Smith 41","Maria Garcia 19"], 
                                 freq=[12345,23431,11322])


     insertcols!( df,([:first,:last,:age] .=>collect.(zip(split.(df.name)...)))...)

instead trying to do something similar with transform! it does not work

     transform!(df, :name => (x-> collect.(zip(split.(x)...))).=>[:first,:last,:age])

could someone help me to find where the error is in the latter version?

2

You have an extra broadcasting at the end. You want

julia> transform!(df, :name => (x-> collect.(zip(split.(x)...)))=>[:first,:last,:age])
1 Like
3

Tanks!

I had been led by the analogy with the insertcols function syntax to use the form with braodcasting.
I’m trying to understand what happens in each step.
For example I have proved that the collect is not necessary.

              transform!(df, :name => (x-> (zip(split.(x)...)))=>[:first,:last,:age])

I’m also still trying to understand the various possibilities of the transform function.
In one of the points in the manual it is explained that you can also use vectors of pairs (symbol, function).
For this I tried the following form:

           transform!(df, [:name => (x->cs)=>cd for (cs,cd) in zip(split.(df.name),[:first,:last,:age])])
4

I’m continuing to study the possibilities of the transform function !.
this is very close to the one I was looking for in order to manage the splits of a column in a general way.

            transform!(df, :name => (x-> split.(x))=>AsTable)

            transform!(df, :name => (x-> split.(x))=>[string("col",i) for i in 1:length(split(df.name[1]))])
5

The most succint is probably

julia> transform(df, :name => ByRow(split) => AsTable)
3×5 DataFrame
 Row │ name             freq   x1         x2         x3        
     │ String           Int64  SubStrin…  SubStrin…  SubStrin… 
─────┼─────────────────────────────────────────────────────────
   1 │ James Smith 39   12345  James      Smith      39
   2 │ Michel Smith 41  23431  Michel     Smith      41
   3 │ Maria Garcia 19  11322  Maria      Garcia     19