This is documentation for Mathematica 3, which was
based on an earlier version of the Wolfram Language.
 Level Level[ expr , levelspec ] gives a list of all subexpressions of expr on levels specified by levelspec. Level[ expr , levelspec , f ] applies f to the list of subexpressions. Level uses the standard level specification described in SectionÂ A.3.6. Level[ expr , -1 ] gives a list of all "atomic" objects in expr. Level traverses expressions in depth-first order, so that the subexpressions in the final list are ordered lexicographically by their indices. See the Mathematica book: Section 2.1.7. See also: Apply, Map, Scan. Further Examples Here are the subexpressions of the polynomial at the first four levels. In[1]:= Out[1]= Here are the subexpressions of the polynomial at the first four levels. In[2]:= Out[2]= Here are the subexpressions of the polynomial at the first four levels. In[3]:= Out[3]= Here are the subexpressions of the polynomial at the first four levels. In[4]:= Out[4]=