USING: help.syntax help.markup kernel prettyprint sequences quotations math ; IN: sequences.lib HELP: map-withn { $values { "seq" sequence } { "quot" quotation } { "n" number } { "newseq" sequence } } { $description "A generalisation of " { $link map } ". The first " { $snippet "n" } " items after the quotation will be " "passed to the quotation given to map-withn for each element in the sequence." } { $examples { $example "USING: math sequences.lib prettyprint ;" "1 2 3 4 { 6 7 8 9 10 } [ + + + + ] 4 map-withn .s" "{ 16 17 18 19 20 }" } } { $see-also each-withn } ; HELP: each-withn { $values { "seq" sequence } { "quot" quotation } { "n" number } } { $description "A generalisation of " { $link each } ". The first " { $snippet "n" } " items after the quotation will be " "passed to the quotation given to each-withn for each element in the sequence." } { $see-also map-withn } ; HELP: sigma { $values { "seq" sequence } { "quot" quotation } { "n" number } } { $description "Like map sum, but without creating an intermediate sequence." } { $example "! Find the sum of the squares [0,99]" "USING: math math.ranges sequences.lib prettyprint ;" "100 [1,b] [ sq ] sigma ." "338350" } ; HELP: count { $values { "seq" sequence } { "quot" quotation } { "n" integer } } { $description "Efficiently returns the number of elements that the predicate quotation matches." } { $example "USING: math math.ranges sequences.lib prettyprint ;" "100 [1,b] [ even? ] count ." "50" } ;