1 USING: help.markup help.syntax sequences strings ;
4 ARTICLE: "grouping" "Groups and clumps"
5 "A virtual sequence for splitting a sequence into disjoint, fixed-length subsequences:"
7 { $subsection <groups> }
8 { $subsection <sliced-groups> }
9 "A virtual sequence for splitting a sequence into overlapping, fixed-length subsequences:"
10 { $subsection clumps }
11 { $subsection <clumps> }
12 { $subsection <sliced-clumps> }
13 "The difference can be summarized as the following:"
15 { "With groups, the subsequences form the original sequence when concatenated:"
16 { $unchecked-example "dup n groups concat sequence= ." "t" }
18 { "With clumps, collecting the first element of each subsequence but the last one, together with the last subseqence, yields the original sequence:"
19 { $unchecked-example "dup n clumps unclip-last >r [ first ] map r> append sequence= ." "t" }
26 { $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."
28 "New groups are created by calling " { $link <groups> } " and " { $link <sliced-groups> } "." }
32 { $values { "seq" "a sequence" } { "n" "a non-negative integer" } { "array" "a sequence of sequences" } }
33 { $description "Splits the sequence into disjoint groups of " { $snippet "n" } " elements and collects the groups into a new array." }
34 { $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." }
36 { $example "USING: splitting prettyprint ;" "{ 3 1 3 3 7 } 2 group ." "{ { 3 1 } { 3 3 } { 7 } }" }
40 { $values { "seq" "a sequence" } { "n" "a non-negative integer" } { "groups" groups } }
41 { $description "Outputs a virtual sequence whose elements are disjoint subsequences of " { $snippet "n" } " elements from the underlying sequence." }
44 "USING: arrays kernel prettyprint sequences splitting ;"
45 "9 >array 3 <groups> dup reverse-here concat >array ." "{ 6 7 8 3 4 5 0 1 2 }"
50 { $values { "seq" "a sequence" } { "n" "a non-negative integer" } { "groups" groups } }
51 { $description "Outputs a virtual sequence whose elements are overlapping subsequences of " { $snippet "n" } " elements from the underlying sequence." }
54 "USING: arrays kernel prettyprint sequences splitting ;"
55 "9 >array 3 <sliced-groups>"
56 "dup [ reverse-here ] each concat >array ."
57 "{ 2 1 0 5 4 3 8 7 6 }"
62 { $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."
64 "New clumps are created by calling " { $link <clumps> } " and " { $link <sliced-clumps> } "." } ;
67 { $values { "seq" "a sequence" } { "n" "a non-negative integer" } { "array" "a sequence of sequences" } }
68 { $description "Splits the sequence into overlapping clumps of " { $snippet "n" } " elements and collects the clumps into a new array." }
69 { $errors "Throws an error if " { $snippet "n" } " is smaller than the length of the sequence." }
71 { $example "USING: splitting prettyprint ;" "{ 3 1 3 3 7 } 2 clump ." "{ { 3 1 } { 1 3 } { 3 3 } { 3 7 } }" }
75 { $values { "seq" "a sequence" } { "n" "a non-negative integer" } { "clumps" clumps } }
76 { $description "Outputs a virtual sequence whose elements are overlapping subsequences of " { $snippet "n" } " elements from the underlying sequence." }
80 "USING: splitting sequences math prettyprint kernel ;"
83 " { 13/50 51/100 13/50 1/10 4/5 17/20 33/50 3/25 19/100 3/100 } ;"
85 "share-price 4 <clumps> [ [ sum ] [ length ] bi / ] map ."
86 "{ 113/400 167/400 201/400 241/400 243/400 91/200 1/4 }"
91 { $values { "seq" "a sequence" } { "n" "a non-negative integer" } { "clumps" clumps } }
92 { $description "Outputs a virtual sequence whose elements are overlapping slices of " { $snippet "n" } " elements from the underlying sequence." } ;
94 { clumps groups } related-words
96 { clump group } related-words
98 { <clumps> <groups> } related-words
100 { <sliced-clumps> <sliced-groups> } related-words