84 lines
3.1 KiB
Factor
Executable File
84 lines
3.1 KiB
Factor
Executable File
IN: histogram
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USING: help.markup help.syntax sequences hashtables quotations assocs ;
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HELP: histogram
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{ $values
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{ "seq" sequence }
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{ "hashtable" hashtable }
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}
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{ $examples
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{ $example "! Count the number of times an element appears in a sequence."
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"USING: prettyprint histogram ;"
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"\"aaabc\" histogram ."
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"H{ { 97 3 } { 98 1 } { 99 1 } }"
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}
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}
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{ $description "Returns a hashtable where the keys are the elements of the sequence and the values are the number of times they appeared in that sequence." } ;
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HELP: histogram*
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{ $values
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{ "hashtable" hashtable } { "seq" sequence }
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{ "hashtable" hashtable }
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}
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{ $examples
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{ $example "! Count the number of times the elements of two sequences appear."
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"USING: prettyprint histogram ;"
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"\"aaabc\" histogram \"aaaaaabc\" histogram* ."
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"H{ { 97 9 } { 98 2 } { 99 2 } }"
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}
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}
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{ $description "Takes an existing hashtable and uses " { $link histogram } " to continue counting the number of occurences of each element." } ;
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HELP: sequence>assoc
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{ $values
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{ "seq" sequence } { "quot" quotation } { "exemplar" "an exemplar assoc" }
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{ "assoc" assoc }
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}
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{ $examples
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{ $example "! Iterate over a sequence and increment the count at each element"
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"USING: assocs prettyprint histogram ;"
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"\"aaabc\" [ inc-at ] H{ } sequence>assoc ."
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"H{ { 97 3 } { 98 1 } { 99 1 } }"
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}
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}
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{ $description "Iterates over a sequence, allowing elements of the sequence to be added to a newly created " { $snippet "assoc" } " according to the passed quotation." } ;
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HELP: sequence>assoc*
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{ $values
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{ "assoc" assoc } { "seq" sequence } { "quot" quotation }
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{ "assoc" assoc }
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}
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{ $examples
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{ $example "! Iterate over a sequence and add the counts to an existing assoc"
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"USING: assocs prettyprint histogram kernel ;"
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"H{ { 97 2 } { 98 1 } } clone \"aaabc\" [ inc-at ] sequence>assoc* ."
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"H{ { 97 5 } { 98 2 } { 99 1 } }"
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}
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}
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{ $description "Iterates over a sequence, allowing elements of the sequence to be added to an existing " { $snippet "assoc" } " according to the passed quotation." } ;
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HELP: sequence>hashtable
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{ $values
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{ "seq" sequence } { "quot" quotation }
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{ "hashtable" hashtable }
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}
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{ $examples
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{ $example "! Count the number of times an element occurs in a sequence"
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"USING: assocs prettyprint histogram ;"
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"\"aaabc\" [ inc-at ] sequence>hashtable ."
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"H{ { 97 3 } { 98 1 } { 99 1 } }"
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}
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}
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{ $description "Iterates over a sequence, allowing elements of the sequence to be added to a hashtable according to the passed quotation." } ;
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ARTICLE: "histogram" "Computing histograms"
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"Counting elements in a sequence:"
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{ $subsection histogram }
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{ $subsection histogram* }
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"Combinators for implementing histogram:"
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{ $subsection sequence>assoc }
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{ $subsection sequence>assoc* }
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{ $subsection sequence>hashtable } ;
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ABOUT: "histogram"
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