nrows(nothing) = 0

Author: ablaom

src/data_utils.jl

@@ -191,6 +191,7 @@ Return the number of rows for a table, abstract vector or matrix `X` $REQUIRE.
 nrows(X) = nrows(get_interface_mode(), vtrait(X), X)
 
 nrows(::Mode, ::Val{:other}, X::AbstractVecOrMat) = size(X, 1)
+nrows(::Mode, ::Val{:other}, X::Nothing) = 0
 
 nrows(::Mode, ::Val{:other}, X) =
     throw(ArgumentError("Function `nrows` only supports AbstractVector or " *

test/data_utils.jl

@@ -97,6 +97,7 @@ end
     @test_throws ArgumentError nrows(X)
     X = (a=[4,2,1],b=[3,2,1])
     @test_throws M.InterfaceError nrows(X)
+    @test nrows(nothing) == 0
 end
 @testset "nrows-full" begin
     setfull()