105 lines
4.7 KiB
Factor
105 lines
4.7 KiB
Factor
USING: help.markup help.syntax sequences strings ;
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IN: grouping
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ARTICLE: "grouping" "Groups and clumps"
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"Splitting a sequence into disjoint, fixed-length subsequences:"
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{ $subsection group }
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"A virtual sequence for splitting a sequence into disjoint, fixed-length subsequences:"
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{ $subsection groups }
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{ $subsection <groups> }
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{ $subsection <sliced-groups> }
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"Splitting a sequence into overlapping, fixed-length subsequences:"
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{ $subsection clump }
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"A virtual sequence for splitting a sequence into overlapping, fixed-length subsequences:"
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{ $subsection clumps }
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{ $subsection <clumps> }
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{ $subsection <sliced-clumps> }
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"The difference can be summarized as the following:"
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{ $list
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{ "With groups, the subsequences form the original sequence when concatenated:"
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{ $unchecked-example "dup n groups concat sequence= ." "t" }
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}
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{ "With clumps, collecting the first element of each subsequence but the last one, together with the last subseqence, yields the original sequence:"
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{ $unchecked-example "dup n clumps unclip-last >r [ first ] map r> append sequence= ." "t" }
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}
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} ;
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ABOUT: "grouping"
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HELP: groups
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{ $class-description "Instances are virtual sequences whose elements are disjoint fixed-length subsequences of an underlying sequence. Groups are mutable and resizable if the underlying sequence is mutable and resizable, respectively."
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$nl
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"New groups are created by calling " { $link <groups> } " and " { $link <sliced-groups> } "." }
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{ $see-also group } ;
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HELP: group
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{ $values { "seq" "a sequence" } { "n" "a non-negative integer" } { "array" "a sequence of sequences" } }
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{ $description "Splits the sequence into disjoint groups of " { $snippet "n" } " elements and collects the groups into a new array." }
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{ $notes "If the sequence length is not a multiple of " { $snippet "n" } ", the final subsequence in the list will be shorter than " { $snippet "n" } " elements." }
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{ $examples
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{ $example "USING: grouping prettyprint ;" "{ 3 1 3 3 7 } 2 group ." "{ { 3 1 } { 3 3 } { 7 } }" }
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} ;
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HELP: <groups>
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{ $values { "seq" "a sequence" } { "n" "a non-negative integer" } { "groups" groups } }
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{ $description "Outputs a virtual sequence whose elements are disjoint subsequences of " { $snippet "n" } " elements from the underlying sequence." }
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{ $examples
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{ $example
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"USING: arrays kernel prettyprint sequences grouping ;"
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"9 >array 3 <groups> dup reverse-here concat >array ." "{ 6 7 8 3 4 5 0 1 2 }"
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}
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} ;
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HELP: <sliced-groups>
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{ $values { "seq" "a sequence" } { "n" "a non-negative integer" } { "groups" groups } }
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{ $description "Outputs a virtual sequence whose elements are overlapping subsequences of " { $snippet "n" } " elements from the underlying sequence." }
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{ $examples
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{ $example
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"USING: arrays kernel prettyprint sequences grouping ;"
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"9 >array 3 <sliced-groups>"
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"dup [ reverse-here ] each concat >array ."
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"{ 2 1 0 5 4 3 8 7 6 }"
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}
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} ;
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HELP: clumps
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{ $class-description "Instances are virtual sequences whose elements are overlapping fixed-length subsequences o an underlying sequence. Clumps are mutable and resizable if the underlying sequence is mutable and resizable, respectively."
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$nl
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"New clumps are created by calling " { $link <clumps> } " and " { $link <sliced-clumps> } "." } ;
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HELP: clump
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{ $values { "seq" "a sequence" } { "n" "a non-negative integer" } { "array" "a sequence of sequences" } }
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{ $description "Splits the sequence into overlapping clumps of " { $snippet "n" } " elements and collects the clumps into a new array." }
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{ $errors "Throws an error if " { $snippet "n" } " is smaller than the length of the sequence." }
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{ $examples
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{ $example "USING: grouping prettyprint ;" "{ 3 1 3 3 7 } 2 clump ." "{ { 3 1 } { 1 3 } { 3 3 } { 3 7 } }" }
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} ;
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HELP: <clumps>
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{ $values { "seq" "a sequence" } { "n" "a non-negative integer" } { "clumps" clumps } }
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{ $description "Outputs a virtual sequence whose elements are overlapping subsequences of " { $snippet "n" } " elements from the underlying sequence." }
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{ $examples
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"Running averages:"
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{ $example
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"USING: grouping sequences math prettyprint kernel ;"
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"IN: scratchpad"
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": share-price"
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" { 13/50 51/100 13/50 1/10 4/5 17/20 33/50 3/25 19/100 3/100 } ;"
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""
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"share-price 4 <clumps> [ [ sum ] [ length ] bi / ] map ."
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"{ 113/400 167/400 201/400 241/400 243/400 91/200 1/4 }"
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}
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} ;
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HELP: <sliced-clumps>
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{ $values { "seq" "a sequence" } { "n" "a non-negative integer" } { "clumps" clumps } }
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{ $description "Outputs a virtual sequence whose elements are overlapping slices of " { $snippet "n" } " elements from the underlying sequence." } ;
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{ clumps groups } related-words
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{ clump group } related-words
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{ <clumps> <groups> } related-words
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{ <sliced-clumps> <sliced-groups> } related-words
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