add deleteat! (#176)

Author: bkamins

src/array.jl

@@ -790,3 +790,5 @@ end
 
 refs(A::CategoricalArray) = A.refs
 pool(A::CategoricalArray) = A.pool
+
+Base.deleteat!(A::CategoricalArray, inds) = (deleteat!(A.refs, inds); A)

test/13_arraycommon.jl

@@ -1094,4 +1094,13 @@ end
     end
 end
 
+@testset "deleteat!" begin
+    x = ['a':'z';]
+    y = categorical(x)
+    deleteat!(x, [1, 3])
+    deleteat!(y, [1, 3])
+    @test x == y
+    @test levels(y) == 'a':'z'
+end
+
 end