StructViews.jl

StructViews.jl lets to view array of structs as struct of field arrays
Author Vitaliy-Yakovchuk
Popularity
3 Stars
Updated Last
1 Year Ago
Started In
November 2019

StructViews.jl

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This package introduces the types StructView and FieldView which are AbstractArray. StructView lets to view array of structs as struct of field arrays. All data are stored in the provided parent array. Parent array may be updated transparently via StructView

Installation

using Pkg; Pkg.add("StructViews")

Example usage to view point coordinates

julia> using StructViews

julia> struct Point
       x
       y
end

julia> points = [Point(i, i + 100) for i in 1:5]
5-element Array{Point,1}:
 Point(1, 101)
 Point(2, 102)
 Point(3, 103)
 Point(4, 104)
 Point(5, 105)

julia> view = StructView(points)
5-element StructView{Point,1,IndexLinear()}:
 Point(1, 101)
 Point(2, 102)
 Point(3, 103)
 Point(4, 104)
 Point(5, 105)

julia> view.x
5-element FieldView{Any,:x,1,IndexLinear(),:immutable}:
 1
 2
 3
 4
 5

julia> view.y
5-element FieldView{Any,:y,1,IndexLinear(),:immutable}:
 101
 102
 103
 104
 105

julia> push!(view, Point(-1, -1))
6-element StructView{Point,1,IndexLinear()}:
 Point(1, 101)
 Point(2, 102)
 Point(3, 103)
 Point(4, 104)
 Point(5, 105)
 Point(-1, -1)

julia> points
6-element Array{Point,1}:
 Point(1, 101)
 Point(2, 102)
 Point(3, 103)
 Point(4, 104)
 Point(5, 105)
 Point(-1, -1)

julia> pop!(view)
Point(-1, -1)

Example usage to view point coordinates, where coordinates are complex numbers

julia> struct ComplexPoint
       x::Complex{Int}
       y::Complex{Int}
end

julia> points = [ComplexPoint(i + 2im, i + 100im) for i in 1:5]
5-element Array{ComplexPoint,1}:
 ComplexPoint(1 + 2im, 1 + 100im)
 ComplexPoint(2 + 2im, 2 + 100im)
 ComplexPoint(3 + 2im, 3 + 100im)
 ComplexPoint(4 + 2im, 4 + 100im)
 ComplexPoint(5 + 2im, 5 + 100im)

julia> view = StructView(points)
5-element StructView{ComplexPoint,1,IndexLinear()}:
 ComplexPoint(1 + 2im, 1 + 100im)
 ComplexPoint(2 + 2im, 2 + 100im)
 ComplexPoint(3 + 2im, 3 + 100im)
 ComplexPoint(4 + 2im, 4 + 100im)
 ComplexPoint(5 + 2im, 5 + 100im)

julia> view.x
5-element StructView{Complex{Int64},1,IndexLinear()}:
 1 + 2im
 2 + 2im
 3 + 2im
 4 + 2im
 5 + 2im

julia> view.y.re
5-element FieldView{Int64,:re,1,IndexLinear(),:immutable}:
 1
 2
 3
 4
 5

Example usage to update fields

StructView lets you to update data in the parent array. If the data in the parent array is mutable the appropriate field will be updated. If the data type in the parant array is immutable the new objects with updated field will be set to the parent array.

julia> points = [ComplexPoint(i + 2im, i + 100im) for i in 1:5]
5-element Array{ComplexPoint,1}:
 ComplexPoint(1 + 2im, 1 + 100im)
 ComplexPoint(2 + 2im, 2 + 100im)
 ComplexPoint(3 + 2im, 3 + 100im)
 ComplexPoint(4 + 2im, 4 + 100im)
 ComplexPoint(5 + 2im, 5 + 100im)

julia> view.y.im .+= 10000
5-element FieldView{Int64,:im,1,IndexLinear(),:immutable}:
 10100
 10100
 10100
 10100
 10100

julia> points
5-element Array{ComplexPoint,1}:
 ComplexPoint(1 + 2im, 1 + 10100im)
 ComplexPoint(2 + 2im, 2 + 10100im)
 ComplexPoint(3 + 2im, 3 + 10100im)
 ComplexPoint(4 + 2im, 4 + 10100im)
 ComplexPoint(5 + 2im, 5 + 10100im)

Example usage to view field

FieldView is a simple field viewer of the array of struct

julia> struct Point
       x
       y
end

julia> points = [Point(i, i + 100) for i in 1:5]
5-element Array{Point,1}:
 Point(1, 101)
 Point(2, 102)
 Point(3, 103)
 Point(4, 104)
 Point(5, 105)

julia> view = FieldView{:x}(points)
5-element FieldView{Any,:x,1,IndexLinear(),:immutable}:
 1
 2
 3
 4
 5

Example usage to update field

Update logic is the same (mutate mutable objects or create a copy with updated field in the parant array)

julia> view[2] = 300
300

julia> points
5-element Array{Point,1}:
 Point(1, 101)  
 Point(300, 102)
 Point(3, 103)  
 Point(4, 104)  
 Point(5, 105)