This is documentation for Mathematica 8, which was
based on an earlier version of the Wolfram Language.
View current documentation (Version 11.1)

Unset

lhs=.
removes any rules defined for lhs.
  • Rules are removed only when their left-hand sides are identical to lhs, up to renaming of patterns.
Undefine a value:
Undefine a function:
Undefine a value:
In[1]:=
Click for copyable input
In[2]:=
Click for copyable input
In[3]:=
Click for copyable input
Out[3]=
 
Undefine a function:
In[1]:=
Click for copyable input
In[2]:=
Click for copyable input
Clear values of variables:
Clear functions (downvalues):
Use to clear definitions with a particular left-hand side:
Clear all definitions:
To clear an upvalue, the tag has to be given:
New in 1