128 lines
4.9 KiB
Factor
128 lines
4.9 KiB
Factor
USING: kernel help.markup help.syntax sequences quotations ;
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IN: sets
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ARTICLE: "sets" "Set-theoretic operations on sequences"
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"Set-theoretic operations on sequences are defined on the " { $vocab-link "sets" } " vocabulary. All of these operations use hashtables internally to achieve linear running time."
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$nl
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"Remove duplicates:"
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{ $subsection prune }
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"Test for duplicates:"
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{ $subsection all-unique? }
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{ $subsection duplicates }
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"Set operations on sequences:"
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{ $subsection diff }
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{ $subsection intersect }
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{ $subsection union }
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"Set-theoretic predicates:"
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{ $subsection intersects? }
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{ $subsection subset? }
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{ $subsection set= }
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"A word used to implement the above:"
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{ $subsection unique }
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"Adding elements to sets:"
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{ $subsection adjoin }
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{ $subsection conjoin }
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{ $see-also member? memq? contains? all? "assocs-sets" } ;
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ABOUT: "sets"
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HELP: adjoin
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{ $values { "elt" object } { "seq" "a resizable mutable sequence" } }
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{ $description "Removes all elements equal to " { $snippet "elt" } ", and adds " { $snippet "elt" } " at the end of the sequence." }
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{ $examples
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{ $example
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"USING: namespaces prettyprint sets ;"
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"V{ \"beans\" \"salsa\" \"cheese\" } \"v\" set"
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"\"nachos\" \"v\" get adjoin"
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"\"salsa\" \"v\" get adjoin"
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"\"v\" get ."
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"V{ \"beans\" \"cheese\" \"nachos\" \"salsa\" }"
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}
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}
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{ $side-effects "seq" } ;
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HELP: conjoin
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{ $values { "elt" object } { "assoc" "an assoc" } }
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{ $description "Stores a key/value pair, both equal to " { $snippet "elt" } ", into the assoc." }
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{ $examples
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{ $example
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"USING: kernel prettyprint sets ;"
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"H{ } clone 1 over conjoin ."
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"H{ { 1 1 } }"
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}
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}
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{ $side-effects "assoc" } ;
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HELP: unique
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{ $values { "seq" "a sequence" } { "assoc" "an assoc" } }
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{ $description "Outputs a new assoc where the keys and values are equal." }
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{ $examples
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{ $example "USING: sets prettyprint ;" "{ 1 1 2 2 3 3 } unique ." "H{ { 1 1 } { 2 2 } { 3 3 } }" }
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} ;
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HELP: prune
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{ $values { "seq" "a sequence" } { "newseq" "a sequence" } }
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{ $description "Outputs a new sequence with each distinct element of " { $snippet "seq" } " appearing only once. Elements are compared for equality using " { $link = } " and elements are ordered according to their position in " { $snippet "seq" } "." }
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{ $examples
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{ $example "USING: sets prettyprint ;" "{ 1 1 t 3 t } prune ." "V{ 1 t 3 }" }
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} ;
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HELP: duplicates
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{ $values { "seq" "a sequence" } { "newseq" "a sequence" } }
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{ $description "Outputs a new sequence consisting of elements which occur more than once in " { $snippet "seq" } "." }
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{ $examples
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{ $example "USING: sets prettyprint ;" "{ 1 2 3 1 2 1 } duplicates ." "{ 1 2 1 }" }
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} ;
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HELP: all-unique?
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{ $values { "seq" sequence } { "?" "a boolean" } }
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{ $description "Tests whether a sequence contains any repeated elements." }
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{ $example
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"USING: sets prettyprint ;"
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"{ 0 1 1 2 3 5 } all-unique? ."
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"f"
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} ;
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HELP: diff
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{ $values { "seq1" sequence } { "seq2" sequence } { "newseq" sequence } }
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{ $description "Outputs a sequence consisting of elements present in " { $snippet "seq1" } " but not " { $snippet "seq2" } ", comparing elements for equality."
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} { $examples
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{ $example "USING: sets prettyprint ;" "{ 1 2 3 } { 2 3 4 } diff ." "{ 1 }" }
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} ;
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HELP: intersect
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{ $values { "seq1" sequence } { "seq2" sequence } { "newseq" sequence } }
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{ $description "Outputs a sequence consisting of elements present in both " { $snippet "seq1" } " and " { $snippet "seq2" } "." }
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{ $examples
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{ $example "USING: sets prettyprint ;" "{ 1 2 3 } { 2 3 4 } intersect ." "{ 2 3 }" }
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} ;
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HELP: union
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{ $values { "seq1" sequence } { "seq2" sequence } { "newseq" sequence } }
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{ $description "Outputs a sequence consisting of elements present in " { $snippet "seq1" } " and " { $snippet "seq2" } " which does not contain duplicate values." }
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{ $examples
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{ $example "USING: sets prettyprint ;" "{ 1 2 3 } { 2 3 4 } union ." "V{ 1 2 3 4 }" }
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} ;
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{ diff intersect union } related-words
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HELP: intersects?
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{ $values { "seq1" sequence } { "seq2" sequence } { "?" "a boolean" } }
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{ $description "Tests if " { $snippet "seq1" } " and " { $snippet "seq2" } " have any elements in common." }
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{ $notes "If one of the sequences is empty, the result is always " { $link f } "." } ;
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HELP: subset?
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{ $values { "seq1" sequence } { "seq2" sequence } { "?" "a boolean" } }
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{ $description "Tests if every element of " { $snippet "seq1" } " is contained in " { $snippet "seq2" } "." }
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{ $notes "If " { $snippet "seq1" } " is empty, the result is always " { $link t } "." } ;
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HELP: set=
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{ $values { "seq1" sequence } { "seq2" sequence } { "?" "a boolean" } }
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{ $description "Tests if both sequences contain the same elements, disregrading order and duplicates." } ;
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HELP: gather
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{ $values
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{ "seq" sequence } { "quot" quotation }
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{ "newseq" sequence } }
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{ $description "Maps a quotation onto a sequence, concatenates the results of the mapping, and removes duplicates." } ;
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