Indexing using tuples

New to Julia
1

I’m trying to use a tuple of strings for indexing a variable (in JuMP). I’m able to loop, etc. but can’t figure out how index a single element. Example, Products is my index tuple, x is my variable.

julia> Products
(“Product1”, “Product2”, “Product3”, “Product4”)

julia> x
1-dimensional DenseAxisArray{VariableRef,1,…} with index sets:
Dimension 1, (“Product1”, “Product2”, “Product3”, “Product4”)
And data, a 4-element Vector{VariableRef}:
x[Product1]
x[Product2]
x[Product3]
x[Product4]

julia>

I want to write x[“Product2”], but this does not work. x[Products[2]] works, but I want to use the actual name, “Product2”.

2

looks identical to me i.e. should just work, can you post runnable code?

3

It seems to have to do with the way the tuple is generated.

When I “hardcode” the tuple, then it works:

julia> Products = (“Product1”, “Product2”, “Product3”, “Product4”)
(“Product1”, “Product2”, “Product3”, “Product4”)

But if I construct the tuple by reading from a file, it does not work:

julia> Products = tuple(Example3_df[:,1]…); # Names of products

julia> Products
(“Product1”, “Product2”, “Product3”, “Product4”)

But the tuple (Products) looks identical to me!

4

What is typeof(Products) when you hardcode it and when you construct it from the file?

5

There is a small difference:
julia> Products = tuple(data_df[:,1]…)
(“Product1”, “Product2”, “Product3”, “Product4”)

julia> typeof(Products)
NTuple{4, String15}

julia> Products = (“Product1”, “Product2”, “Product3”, “Product4”)
(“Product1”, “Product2”, “Product3”, “Product4”)

julia> typeof(Products)
NTuple{4, String}

6

GitHub - JuliaStrings/InlineStrings.jl: Fixed-width string types for Julia gripe I guess…the bandaid solution right now is to String.(tuple(data_df[:,1]…)) probably

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