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 formi.

Examples

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Basic Examples  (1)

Define values and attributes for a symbol:

Clear values and attributes:

Scope  (4)

Clear values of variables:

Clear functions (downvalues):

Clear upvalues:

Clear several symbols:

Generalizations & Extensions  (2)

Clear all symbols in a given context:

Specify symbols to clear as string patterns:

Applications  (2)

Clear any old definitions before making new ones:

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

Properties & Relations  (2)

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:

Possible Issues  (1)

Protected symbols cannot be cleared:

Use Unprotect to clear definitions of protected symbols:

Neat Examples  (1)

Clear the definitions of all symbols in the current context:

Introduced in 1988
 (1.0)