Attributes
 Usage
• Attributes[symbol] gives the list of attributes for a symbol.
Notes
• The attributes of a symbol can be set by assigning a value to Attributes[s]. If a single attribute is assigned, it need not be in a list. • Attributes[s] = {} clears all attributes of a symbol. • Attributes[{ ,  , ... }] gives a list of the attributes for each of the  . • Attributes["str"] gives a list of the attributes for all symbols which match the string pattern str. • Attributes[HoldPattern[s]] is treated as equivalent to Attributes[s]. • Attributes for functions must be set before any definitions that involve the functions are given. • The complete list of possible attributes for a symbol f is:
| Constant | all derivatives of f are zero | | Flat | f is associative | | HoldAll | all the arguments of f are not evaluated | | HoldAllComplete | the arguments of f are completely shielded from evaluation | | HoldFirst | the first argument of f is not evaluated | | HoldRest | all but the first argument of f are not evaluated | | Listable | f is automatically "threaded" over lists | | Locked | attributes of f cannot be changed | | NHoldAll | the arguments of f are not affected by N | | NHoldFirst | the first argument of f is not affected by N | | NHoldRest | all but the first argument of f are not affected by N | | NumericFunction | the value of f is assumed to be a number when its arguments are numbers | | OneIdentity | f[a], f[f[a]], etc. are equivalent to a in pattern matching | | Orderless | f is commutative | | Protected | values of f cannot be changed | | ReadProtected | values of f cannot be read | | SequenceHold | Sequence objects in the arguments of f are not flattened out | | Stub | Needs is automatically called if the symbol is ever input | | Temporary | f is a local variable, removed when no longer used |
• New in Version 1; modified in 3.
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