Merge pull request #43 from JuliaArrays/teh/getaxis

Extract a specific axis via ax = A[Axis{:t}]

Author: timholy

src/indexing.jl

@@ -202,3 +202,9 @@ end
     meta = Expr(:meta, :inline)
     return :($meta; $ex)
 end
+
+## Extracting the full axis (name + values) from the Axis{:name} type
+@inline Base.getindex{Ax<:Axis}(A::AxisArray, ::Type{Ax}) = getaxis(Ax, axes(A)...)
+@inline getaxis{Ax<:Axis}(::Type{Ax}, ax::Ax, axs...) = ax
+@inline getaxis{Ax<:Axis}(::Type{Ax}, ax::Axis, axs...) = getaxis(Ax, axs...)
+@noinline getaxis{Ax<:Axis}(::Type{Ax}) = throw(ArgumentError("no axis of type $Ax was found"))

test/indexing.jl

@@ -95,3 +95,12 @@ A = AxisArray(reshape(1:15, 3, 5), :x, :y)
 @test A[2,2,CartesianIndex(())] == 5
 @test A[2,CartesianIndex(()),2] == 5
 @test A[CartesianIndex(()),2,2] == 5
+
+# Extracting the full axis
+axx = @inferred(A[Axis{:x}])
+@test isa(axx, Axis{:x})
+@test axx.val == 1:3
+axy = @inferred(A[Axis{:y}])
+@test isa(axy, Axis{:y})
+@test axy.val == 1:5
+@test_throws ArgumentError A[Axis{:z}]