Pair slicing (#49)

Author: mtfishman

Project.toml

@@ -1,7 +1,7 @@
 name = "NamedDimsArrays"
 uuid = "60cbd0c0-df58-4cb7-918c-6f5607b73fde"
 authors = ["ITensor developers <support@itensor.org> and contributors"]
-version = "0.5.3"
+version = "0.5.4"
 
 [deps]
 Adapt = "79e6a3ab-5dfb-504d-930d-738a2a938a0e"

src/abstractnameddimsarray.jl

@@ -587,6 +587,11 @@ function Base.view(a::AbstractNamedDimsArray, I1::NamedViewIndex, Irest::NamedVi
     view(dename(a), subinds...), sub_nameddimsindices
   )
 end
+function Base.view(a::AbstractNamedDimsArray, I1::Pair, Irest::Pair...)
+  I = (I1, Irest...)
+  nameddimsindices = to_nameddimsindices(a, first.(I))
+  return view(a, map((i, name) -> name[i], last.(I), nameddimsindices)...)
+end
 
 function Base.getindex(
   a::AbstractNamedDimsArray, I1::NamedViewIndex, Irest::NamedViewIndex...

test/test_basics.jl

@@ -160,6 +160,26 @@ using Test: @test, @test_throws, @testset
     @test dimnames(na) == ("i",)
     @test dename(na) == a
 
+    # slicing
+    a = randn(elt, 3, 3)
+    na = NamedDimsArray(a, ("i", "j"))
+    for na′ in (na[named(2:3, "i"), named(2:3, "j")], na["i" => 2:3, "j" => 2:3])
+      @test nameddimsindices(na′) == (named(2:3, "i"), named(2:3, "j"))
+      @test dename(na′) == a[2:3, 2:3]
+      @test dename(na′) isa typeof(a)
+    end
+
+    # view slicing
+    a = randn(elt, 3, 3)
+    na = NamedDimsArray(a, ("i", "j"))
+    for na′ in
+        (@view(na[named(2:3, "i"), named(2:3, "j")]), @view(na["i" => 2:3, "j" => 2:3]))
+      @test nameddimsindices(na′) == (named(2:3, "i"), named(2:3, "j"))
+      @test copy(dename(na′)) == a[2:3, 2:3]
+      @test dename(na′) === @view(a[2:3, 2:3])
+      @test dename(na′) isa SubArray{elt,2}
+    end
+
     # aliasing
     a′ = randn(elt, 2, 2)
     i = Name("i")