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 Documentation / Mathematica / Built-in Functions / Programming / Expression Structure  /
Head

  • Head[ expr ] gives the head of expr.
  • Examples: Head[f[x]]; Head[a + b]; Head[4]; Head[x].
  • See the Mathematica book: Section 2.1.1Section 2.1.1.

    Further Examples

    Here are the heads of various numbers in Mathematica.

    In[1]:=

    Out[1]=

    Looking at the heads of these expressions gives some insight into their internal representation. For the whole story, use FullForm.

    In[2]:=

    Out[2]=

    In[3]:=

    Out[3]=