ArrayDepth[expr] gives the depth to which expr is a full array, with all the parts at a particular level being lists of the same length, or is a SparseArray object. Ok, so ArrayDepth of a symbol (i.e. a scalar quantity) gives 0: In[1]:= ArrayDepth[f] Out[1]:= 0 But: In[2]:= ArrayDepth[f[x]] Out[2]:= 1 Why? f[x] is stillRead more