diff --git a/src/axes.jl b/src/axes.jl
index 08d060f8..e411fdc3 100644
--- a/src/axes.jl
+++ b/src/axes.jl
@@ -462,8 +462,8 @@ end
 # add the discrete value for each item.  return the continuous values and the indices
 function discrete_value!(axis::Axis, v::AVec)
     n = linearindices(v)
-    cvec = zeros(n)
-    discrete_indices = zeros(Int, n)
+    cvec = zeros(length(n))
+    discrete_indices = zeros(Int, length(n))
     for i=n
         cvec[i], discrete_indices[i] = discrete_value!(axis, v[i])
     end