Not with non-existing columns

[Lincoln-Hannah]

x = DataFrame(a=1:2,b=2:3)

might be nice to support

x[:,Not(:a,:c)]

instead of having to write

x[:,Not( [:a,:c] ∩ propertynames(x) )]

[bkamins]

Unfortunately, this is not how Not was designed to work in general (outside of DataFrames.jl):

julia> x = [1, 2, 3]
3-element Vector{Int64}:
 1
 2
 3

julia> x[Not(4)]
ERROR: BoundsError: attempt to access 3-element Vector{Int64} at index [Not(4)]

so we have to stick to the same rules.

However, a way to do what you want uses Cols and ∉:

julia> x[:, Cols(∉(["a", "c"]))]
2×1 DataFrame
 Row │ b
     │ Int64
─────┼───────
   1 │     2
   2 │     3

or equivalent:

julia> x[:, Cols(!in(["a", "c"]))]
2×1 DataFrame
 Row │ b
     │ Int64
─────┼───────
   1 │     2
   2 │     3