AggregatedEntityClass

AggregatedEntityClass[class,"prop"f]

represents an entity class containing a single entity with the property prop whose value is the result of applying the function f to the whole specified entity class.

AggregatedEntityClass[class,{"prop1"f1,"prop2"f2,}]

constructs multiple properties propi obtained by applying fi to class.

AggregatedEntityClass[class,propspec,gprop]

forms groups of elements of class according to their values of the property gprop, then generates an entity class with an entity for each of these groups.

AggregatedEntityClass[class,propspec,"pname"f]

forms groups according to the values obtained by applying the entity function f, with the resulting property named pname.

AggregatedEntityClass[class,propspec,{gspec1,gspec2,}]

forms groups for which the set of values defined by the gspeci is distinct.

Details

Examples

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Basic Examples  (3)

Create an aggregation of all countries and compute their total area:

An equivalent computation, suitable for small datasets:

Find the mean atomic mass for elements in each period class:

When used with relational-database-backed entities, a two-argument AggregatedEntityClass corresponds to using aggregate functions in the SELECT statement:

Compute the total amount of payments:

Compute the maximum credit limit by country (similar to a GROUP BY statement in SQL languages):

Scope  (2)

The third argument can be an EntityFunction:

Apply a function to the result, typically an aggregation function:

Use this to compute the mean value of the result:

Or create a pie chart with the result:

Properties & Relations  (2)

AggregatedEntityClass generates entities that correspond to groups:

Single entities obtained from AggregatedEntityClass effectively correspond to implicit entities:

Wolfram Research (2019), AggregatedEntityClass, Wolfram Language function, https://reference.wolfram.com/language/ref/AggregatedEntityClass.html.

Text

Wolfram Research (2019), AggregatedEntityClass, Wolfram Language function, https://reference.wolfram.com/language/ref/AggregatedEntityClass.html.

BibTeX

@misc{reference.wolfram_2021_aggregatedentityclass, author="Wolfram Research", title="{AggregatedEntityClass}", year="2019", howpublished="\url{https://reference.wolfram.com/language/ref/AggregatedEntityClass.html}", note=[Accessed: 17-June-2021 ]}

BibLaTeX

@online{reference.wolfram_2021_aggregatedentityclass, organization={Wolfram Research}, title={AggregatedEntityClass}, year={2019}, url={https://reference.wolfram.com/language/ref/AggregatedEntityClass.html}, note=[Accessed: 17-June-2021 ]}

CMS

Wolfram Language. 2019. "AggregatedEntityClass." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/AggregatedEntityClass.html.

APA

Wolfram Language. (2019). AggregatedEntityClass. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/AggregatedEntityClass.html