SubValues

SubValues[f]

gives a list of transformation rules corresponding to all subvalues (values for f[][]) defined for the symbol f.

SubValues["symbol"]

gives a list of transformation rules corresponding to all subvalues defined for the symbol named "symbol" if it exists.

Details and Options

  • You can specify the subvalues for f by making an assignment of the form SubValues[f]=list.
  • The list returned by SubValues has elements of the form HoldPattern[lhs]:>rhs.

Examples

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Basic Examples  (1)

Define subvalues for a symbol f:

These are the subvalues associated with f:

Scope  (4)

SubValues returns rules corresponding to subvalues defined for a symbol:

SubValues can be defined for heads of any depth:

Create several values:

Obtain the subvalues of functions whose names start with f:

SubValues can be used to set the values directly:

Applications  (3)

Create a data object for properties that can be extracted:

These definitions are stored as SubValues:

Extract all the properties from a given object:

The resulting rules are in the order given:

Now reorder the definitions:

Copy a symbol's definitions to another symbol:

Properties & Relations  (5)

Values can be defined by immediate or delayed assignments:

HoldPattern is used to protect the rules from their own definitions:

Without the HoldPattern, the left-hand side would have evaluated:

SubValues["sym"] will issue a message if the specified symbol does not exist:

If the symbol exists but has no definitions, an empty list is returned:

Definition and Information display subvalues but do not return them as values:

SubValues returns a value that can be used in a program:

Evaluation of an expression involves applying matching subvalues:

Wolfram Research (1991), SubValues, Wolfram Language function, https://reference.wolfram.com/language/ref/SubValues.html (updated 2022).

Text

Wolfram Research (1991), SubValues, Wolfram Language function, https://reference.wolfram.com/language/ref/SubValues.html (updated 2022).

CMS

Wolfram Language. 1991. "SubValues." Wolfram Language & System Documentation Center. Wolfram Research. Last Modified 2022. https://reference.wolfram.com/language/ref/SubValues.html.

APA

Wolfram Language. (1991). SubValues. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/SubValues.html

BibTeX

@misc{reference.wolfram_2024_subvalues, author="Wolfram Research", title="{SubValues}", year="2022", howpublished="\url{https://reference.wolfram.com/language/ref/SubValues.html}", note=[Accessed: 13-July-2024 ]}

BibLaTeX

@online{reference.wolfram_2024_subvalues, organization={Wolfram Research}, title={SubValues}, year={2022}, url={https://reference.wolfram.com/language/ref/SubValues.html}, note=[Accessed: 13-July-2024 ]}