BUILT-IN MATHEMATICA SYMBOL

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 sequence of subexpressions.

Details and Options Details and Options

Level uses standard level specifications:
n levels 1 through

Infinity levels 1 through Infinity

{n} level only

{n₁,n₂} levels through
Level[expr, {-1}] gives a list of all "atomic" objects in expr.
A positive level consists of all parts of expr specified by indices.
A negative level consists of all parts of expr with depth .
Level 0 corresponds to the whole expression.
With the option setting Heads->True, Level includes heads of expressions and their parts.
Level traverses expressions in depth-first order, so that the subexpressions in the final list are ordered lexicographically by their indices.