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Julia:How to access an element in an array of a type based on the type field with specific value

I have an array of self defined type, called links, which its elements are of type Link.

type Link
    first::Int64
    second::Int64
    value::Array{Float64,1}
end

, and moreover for links, the typeof(links) is a Vector{Link}.

As you might have guessed, this is part of a graph definition that I have, which includes edges, and first refers to one endpoint and second refers to another endpoint. What I want to do is to select the value of a link in links where the the endpoint first is equal to a specific node number, let's call it vertex_id. so in short I want the following:

value of all those in links, whose .first == vertex_id.

P.S, I know that for DataFrames of regular types, I can say 

df[df[:col1] .== x,:col2]

But is there a similar way to do this for array of a self defined type?

Solution

  • I realized that I can do comprehensions: 

    [x.value for x in links if x.first == vertex_id]