is an option for functions which use level specifications that specifies whether heads of expressions should be included.


  • Heads->True treats heads just like other elements of expressions for the purpose of levels.
  • Heads->False never includes heads as part of any level of an expression.
  • Most functions which use level specifications have the default setting Heads->False. One exception is Position, for which the default is Heads->True.


open allclose all

Basic Examples  (1)

Scope  (2)

Map f also onto the head:

Parts inside heads are included if appropriate level specifications are given:

Introduced in 1991