Index Array without Elements

Question

I have a vector

a = Vector(1:4)

[1, 2, 3, 4]

and I want to index it to all elements but the third to get

[1,         


        

Answer 1

This use case is a common one and is covered by the InvertedIndices.jl package. If you install it then you can run:

julia> using InvertedIndices

julia> a = 1:4
1:4

julia> a[Not(3)]
3-element Array{Int64,1}:
 1
 2
 4

Also some packages (like DataFrames.jl) automatically load this package (so if you e.g. use DataFrames.jl you do not have to install and load InvertedIndices.jl separately).