no method matching InvertedIndex(::String, ::String)

[pdeffebach]

Not("var_1", "var_2")

fails. I think that we want it to work, right?

[bkamins]

This API is not supported by InvertedIndices.jl, so it is up to us to decide if we want to support it or not (it will be a small type piracy). The current API is Not(All("var_1", "var_2")).

[bkamins]

or Not(["var_1", "var_2"]).

[pdeffebach]

Can we ask InvertedIndices to add this?

[bkamins]

Sure we can ask - if you open an issue there can you CC me please?

[pdeffebach]

We might have to resort to type piracy since if we wanted more consistency we would want

Not(:a, [:b, :c]) == Not(:a, :b, :c)

Which would probably cause problems in a lot of other applications of InvertedIndices. But we will see.

[bkamins]

Yes, and I think it will not be that problematic. I guess you want the following invariant:

Not(args...) == Not(Cols(args...))

right?

[bkamins]

ah - probably not - as in the other PR you want to allow non-existent columns in Not. So this is more complex then.

[pdeffebach]

I can still move that PR forward and we will cross that bridge when we come to it.

[bkamins]

This works:

julia> df = DataFrame(a=1,b=2,c=3)
1×3 DataFrame
 Row │ a      b      c
     │ Int64  Int64  Int64
─────┼─────────────────────
   1 │     1      2      3

julia> df[:, Not([:a, :b])]
1×1 DataFrame
 Row │ c
     │ Int64
─────┼───────
   1 │     3

and I think it is sufficient. Allowing multiple arguments to Not could be confusing.

If you feel otherwise please reopen.