Dimensions

Dimensions[expr] finds the dimensions of expr.

Attributes[Dimensions] := {Protected}

Simple examples

In[1]:= Dimensions[{{1, 3}, {1, 2}}]
Out[1]= {2, 2}

In[2]:= Dimensions[{{{1, 2}, {3, 2}}, {{1, 2}}}]
Out[2]= {2}

Further examples

In[1]:= Dimensions[foo]
Out[1]= {}

Dimensions works with any head, not just List:

In[2]:= Dimensions[foo[]]
Out[2]= {0}