Name Rascal/Libraries/Prelude/Relation/groupDomainByRange

Synopsis Make sets of elements in the domain that relate to the same element in the range.

Function set[set[&U]] groupDomainByRange(rel[&U dom, &T ran] input)

Usage import Relation;

Examples

rascal>import Relation;
ok
rascal>legs = {<"bird", 2>, <"dog", 4>, <"human", 2>, <"spider", 8>, <"millepede", 1000>, <"crab", 8>, <"cat", 4>};
rel[str,int]: {
  <"spider",8>,
  <"human",2>,
  <"crab",8>,
  <"cat",4>,
  <"dog",4>,
  <"bird",2>,
  <"millepede",1000>
}
rascal>groupDomainByRange(legs);
set[set[str]]: {
  {"human","bird"},
  {"cat","dog"},
  {"spider","crab"},
  {"millepede"}
}

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