RosettaCodeData/Task/Probabilistic-choice/AppleScript/probabilistic-choice-1.appl...

63 lines
2.7 KiB
AppleScript

use AppleScript version "2.5" -- Mac OS X 10.11 (El Capitan) or later.
use framework "Foundation"
use framework "GameplayKit"
on probabilisticChoices(mapping, picks)
script o
property mapping : {}
end script
-- Make versions of the mapping records with additional 'actual' properties …
set mapping to current application's class "NSMutableArray"'s arrayWithArray:(mapping)
tell mapping to makeObjectsPerformSelector:("addEntriesFromDictionary:") withObject:({actual:0})
-- … ensuring that they're sorted (for accuracy) in descending order (for efficiency) of probability.
set descriptor to current application's class "NSSortDescriptor"'s sortDescriptorWithKey:("probability") ascending:(false)
tell mapping to sortUsingDescriptors:({descriptor})
set o's mapping to mapping as list
set rndGenerator to current application's class "GKRandomDistribution"'s distributionForDieWithSideCount:(picks)
set onePickth to 1 / picks
repeat picks times
-- Get a random number between 0.0 and 1.0.
set r to rndGenerator's nextUniform()
-- Interpret the probability of the number occurring in the range it does
-- as picking the item with the same probability of being picked.
repeat with thisRecord in o's mapping
set r to r - (thisRecord's probability)
if (r 0) then
set thisRecord's actual to (thisRecord's actual) + onePickth
exit repeat
end if
end repeat
end repeat
return o's mapping
end probabilisticChoices
on task()
set mapping to {{|item|:"aleph", probability:1 / 5}, {|item|:"beth", probability:1 / 6}, ¬
{|item|:"gimel", probability:1 / 7}, {|item|:"daleth", probability:1 / 8}, ¬
{|item|:"he", probability:1 / 9}, {|item|:"waw", probability:1 / 10}, ¬
{|item|:"zayin", probability:1 / 11}, {|item|:"heth", probability:1759 / 27720}}
set picks to 1000000
set theResults to probabilisticChoices(mapping, picks)
set output to {}
set template to {"|item|:", missing value, ", probability:", missing value, ", actual:", missing value}
set astid to AppleScript's text item delimiters
set AppleScript's text item delimiters to ""
repeat with thisRecord in theResults
set {|item|:item 2 of template, probability:item 4 of template, actual:item 6 of template} to thisRecord
set {|item|:template's second item, probability:template's fourth item, actual:template's sixth item} to thisRecord
set end of output to template as text
end repeat
set AppleScript's text item delimiters to "}, ¬
{"
set output to "{ ¬
{" & output & "} ¬
}"
set AppleScript's text item delimiters to astid
return output
end task
task()