Added ability to convert from Arrays of Nullables

src/constructors.jl

@@ -96,9 +96,30 @@ function NullableArray{T}(A::AbstractArray,
 end
 
 #----- Constructor #7 --------------------------------------------------------#
-
 # The following method allows for the construction of zero-element
 # NullableArrays by calling the parametrized type on zero arguments.
 # TODO: add support for dimensions arguments?
 @compat (::Type{NullableArray{T, N}}){T, N}() = NullableArray(T, ntuple(i->0, N))
 
+#----- Conversion from Array of Nullables #1 -----------------------------------#
+# Take an Array of Nullable objects and convert it into a NullableArray
+function Base.convert{S, T, N}(::Type{NullableArray{S, N}}, in::AbstractArray{Nullable{T}, N})
+ out = NullableArray{S, N}(Array(S, size(in)), Array(Bool, size(in)))
+ for i = 1:length(in)
+ if !(out.isnull[i] = isnull(in[i]))
+ out.values[i] = in[i].value
+ end
+ end
+ out
+end
+
+#----- Conversion from Array of Nullables #2 -----------------------------------#
+# Take an Array of Nullable objects and convert it into a NullableArray
+# A slightly more convenient syntax to match the type of the input
+Base.convert{S, T, N}(::Type{NullableArray{S}}, in::AbstractArray{Nullable{T}, N}) = Base.convert(NullableArray{S, N}, in)
+
+#----- Constructor #8 -----------------------------------#
+# Take an Array of Nullable objects and convert it into a NullableArray
+# The constructor needs defining as it is a more specialized version of the
+# above, and thus will not fall back to convert.
+NullableArray{T, N}(in::Array{Nullable{T}, N}) = Base.convert(NullableArray{T, N}, in)

test/constructors.jl

@@ -65,5 +65,16 @@ module TestConstructors
  @test isequal(NullableArray{Bool, 2}(),
  NullableArray{Bool, 2}(Array(Bool, 0, 0)))
 
-
+ # test conversion from arrays of nullables
+ array_of_nulls = Nullable{Int}[Nullable(1), Nullable(2), Nullable(3), Nullable()]
+ @test isa(NullableArray(array_of_nulls), NullableArray{Int,1})
+ @test isequal(NullableArray(array_of_nulls), NullableArray{Int,1}([1,2,3,4],[false,false,false,true]))
+ @test isa(NullableArray{Int64}(array_of_nulls), NullableArray{Int,1})
+ @test isequal(NullableArray{Int64}(array_of_nulls), NullableArray{Int,1}([1,2,3,4],[false,false,false,true]))
+ @test isa(NullableArray{Float64}(array_of_nulls), NullableArray{Float64,1})
+ @test isequal(NullableArray{Float64}(array_of_nulls), NullableArray{Float64,1}([1.0,2.0,3.0,4.0],[false,false,false,true]))
+ @test isa(NullableArray{Int64,1}(array_of_nulls), NullableArray{Int,1})
+ @test isequal(NullableArray{Int64,1}(array_of_nulls), NullableArray{Int,1}([1,2,3,4],[false,false,false,true]))
+ @test isa(NullableArray{Float64,1}(array_of_nulls), NullableArray{Float64,1})
+ @test isequal(NullableArray{Float64,1}(array_of_nulls), NullableArray{Float64,1}([1.0,2.0,3.0,4.0],[false,false,false,true]))
 end