! Copyright (c) 2012 Anonymous ! See http://factorcode.org/license.txt for BSD license. USING: accessors assocs io kernel math.parser sequences sorting ; IN: rosetta-code.top-rank ! http://rosettacode.org/wiki/Top_rank_per_group ! Find the top N salaries in each department, where N is ! provided as a parameter. ! Use this data as a formatted internal data structure (adapt it ! to your language-native idioms, rather than parse at runtime), ! or identify your external data source: ! Employee Name,Employee ID,Salary,Department ! Tyler Bennett,E10297,32000,D101 ! John Rappl,E21437,47000,D050 ! George Woltman,E00127,53500,D101 ! Adam Smith,E63535,18000,D202 ! Claire Buckman,E39876,27800,D202 ! David McClellan,E04242,41500,D101 ! Rich Holcomb,E01234,49500,D202 ! Nathan Adams,E41298,21900,D050 ! Richard Potter,E43128,15900,D101 ! David Motsinger,E27002,19250,D202 ! Tim Sampair,E03033,27000,D101 ! Kim Arlich,E10001,57000,D190 ! Timothy Grove,E16398,29900,D190 TUPLE: employee name id salary department ; CONSTANT: employees { T{ employee f "Tyler Bennett" "E10297" 32000 "D101" } T{ employee f "John Rappl" "E21437" 47000 "D050" } T{ employee f "George Woltman" "E00127" 53500 "D101" } T{ employee f "Adam Smith" "E63535" 18000 "D202" } T{ employee f "Claire Buckman" "E39876" 27800 "D202" } T{ employee f "David McClellan" "E04242" 41500 "D101" } T{ employee f "Rich Holcomb" "E01234" 49500 "D202" } T{ employee f "Nathan Adams" "E41298" 21900 "D050" } T{ employee f "Richard Potter" "E43128" 15900 "D101" } T{ employee f "David Motsinger" "E27002" 19250 "D202" } T{ employee f "Tim Sampair" "E03033" 27000 "D101" } T{ employee f "Kim Arlich" "E10001" 57000 "D190" } T{ employee f "Timothy Grove" "E16398" 29900 "D190" } } : prepare-departments ( seq -- departments ) [ department>> ] collect-by [ [ salary>> ] inv-sort-with ] assoc-map ; : first-n-each ( seq n quot -- ) [ short head-slice ] dip each ; inline : top-rank-main ( -- ) employees prepare-departments [ [ "Department " write write ":" print ] dip 3 [ [ id>> write " $" write ] [ salary>> number>string write " " write ] [ name>> print ] tri ] first-n-each nl ] assoc-each ; MAIN: top-rank-main