Help me with repeated index

using JuMP,SCS


branch=[1 2 0.1
        3 4 0.1 
        4 5 0.2
        4 6 0.3
        5 6 0.1

If we want only the first column of the branch, what we have to do ?

I mean , if I write like this this

S=[(branch[r,1]) for r= 1:size(branch,1)]

I’m getting the error.

Like this

ERROR: LoadError: Repeated index 4.0. Index sets must have unique elements.

Please help me

You cannot create a JuMP variable with duplicate indices. See, e.g.,

model = Model()
@variable(model, x[[:a, :a, :b]])
x[:a]  # Which `:a` is this referring to?

As I said in the other post, you probably intend

model = Model()
@variable(model, v[1:size(branch, 1)])
v[3]  # Corresponds to (4, 5, 0.2)

p.s. Please don’t open multiple posts with the same question: Help me with indexing. It can lead to the answers being split over multiple posts.