Define a getindex method for retrieving only a certain collection from a StructArray of Stars?

[islent]

Hello @elehcim, I have the same problem when plotting a certain collection of particles in AstroPlot.jl. For example, I manually filter the collection in https://github.com/JuliaAstroSim/AstroPlot.jl/blob/5cda583666557c88049eb54e99b5e1a6be2c13c5/src/snapshots/positions.jl#L21:

function plot_positionslice!(scene, data, collection::Collection, u::Union{Nothing, Unitful.FreeUnits} = nothing; kw...)
    d = filter(p->p.Collection == collection, data)
    if isempty(d)
        @warn "No $collection particle found."
        return scene
    else
        plot_positionslice!(scene, d, u; kw...)
    end
end

During simulation, particles are transmited between processors. I can't figure out a way to avoid filtering :(

(As metioned in JuliaAstroSim/AstroIO.jl#8)

[islent]

Oh, I did not notice #22
Close.
Many thanks!