Built-in Mathematica Symbol

ClearAll

ClearAll[symb₁, symb₂, ...]
clears all values, definitions, attributes, messages and defaults associated with symbols.

ClearAll["form₁", "form₂", ...]
clears all symbols whose names textually match any of the form_i.

Define values and attributes for a symbol:

Clear values and attributes:

Define values and attributes for a symbol:

Clear values and attributes:

Clear values of variables:

Clear functions (downvalues):

Clear upvalues:

Clear several symbols:

Clear all symbols in a given context:

Specify symbols to clear as string patterns:

Clear any old definitions before making new ones:

Unprotect and clear all symbols in a package, to allow it to be read twice:

Clear does not remove defaults, options or attributes:

Use ClearAll to clear everything:

Use =. to clear definitions with a particular left-hand side:

Clear all definitions:

Protected symbols cannot be cleared:

Use Unprotect to clear definitions of protected symbols:

Clear the definitions of all symbols in the current context: