Mathematica 9 is now available
THIS IS DOCUMENTATION FOR AN OBSOLETE PRODUCT.
SEE THE DOCUMENTATION CENTER FOR THE LATEST INFORMATION.
Mathematica > Core Language > Expressions > Parts of Expressions > Heads >

Heads

Heads
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.
In[1]:=
Click for copyable input
Out[1]=
In[2]:=
Click for copyable input
Out[2]=
Map also onto the head:
Parts inside heads are included if appropriate level specifications are given:
New in 2
Ask a question about this page  |  Suggest an improvement  |  Leave a message for the team
Format:   HTML  |  CDF