Support vectors as indices to NamedTuple

Fix #32662, #27021

NEWS.md

@@ -33,6 +33,7 @@ New library functions
 * New `findall(pattern, string)` method where `pattern` is a string or regex ([#31834]).
 * `istaskfailed` is now documented and exported, like its siblings `istaskdone` and `istaskstarted` ([#32300]).
 * `RefArray` and `RefValue` objects now accept index `CartesianIndex()` in  `getindex` and `setindex!` ([#32653])
+* `NamedTuple`s may now be subsetted with `getindex` ([#27021], [#32662])
 
 Standard library changes
 ------------------------

base/namedtuple.jl

@@ -103,6 +103,8 @@ firstindex(t::NamedTuple) = 1
 lastindex(t::NamedTuple) = nfields(t)
 getindex(t::NamedTuple, i::Int) = getfield(t, i)
 getindex(t::NamedTuple, i::Symbol) = getfield(t, i)
+getindex(t::NamedTuple, v::AbstractVector{<:Integer}) = (; map(i->keys(t)[i] => t[i], v)...)
+getindex(t::NamedTuple, v::AbstractVector{Symbol}) = (; map(i->i => t[i], v)...)
 indexed_iterate(t::NamedTuple, i::Int, state=1) = (getfield(t, i), i+1)
 isempty(::NamedTuple{()}) = true
 isempty(::NamedTuple) = false

test/namedtuple.jl

@@ -21,6 +21,10 @@
 @test (a=3,)[:a] == 3
 @test (x=4, y=5, z=6).y == 5
 @test (x=4, y=5, z=6).z == 6
+@test (x=4, y=5, z=6)[1:1] == (x=4,)
+@test (x=4, y=5, z=6)[1:2] == (x=4, y=5)
+@test (x=4, y=5, z=6)[[1,3]] == (x=4, z=6)
+@test (x=4, y=5, z=6)[[:x,:y]] == (x=4, y=5)
 @test_throws ErrorException (x=4, y=5, z=6).a
 @test_throws BoundsError (a=2,)[0]
 @test_throws BoundsError (a=2,)[2]