Unique characters: Difference between revisions
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return uniqueCharacters({"133252abcdeeffd", "a6789798st", "yxcdfgxcyz"}) |
return uniqueCharacters({"133252abcdeeffd", "a6789798st", "yxcdfgxcyz"}) |
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end considering</lang> |
end considering</lang> |
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===Functional=== |
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Composing a solution from existing generic primitives, for speed of drafting and refactoring, and for high levels of code reuse. |
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<lang applescript>use framework "Foundation" |
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-------------------- UNIQUE CHARACTERS ------------------- |
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-- uniques :: [String] -> String |
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on uniques(xs) |
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script single |
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on |λ|(x) |
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if 1 = length of x then |
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item 1 of x |
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else |
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{} |
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end if |
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end |λ| |
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end script |
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concatMap(single, ¬ |
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group(sort(concatMap(my chars, xs)))) |
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end uniques |
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--------------------------- TEST ------------------------- |
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on run |
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uniques({"133252abcdeeffd", "a6789798st", "yxcdfgxcyz"}) |
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--> {"1", "5", "6", "b", "g", "s", "t", "z"} |
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end run |
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------------------------- GENERIC ------------------------ |
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-- chars :: String -> [Char] |
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on chars(s) |
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characters of s |
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end chars |
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-- concatMap :: (a -> [b]) -> [a] -> [b] |
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on concatMap(f, xs) |
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set lng to length of xs |
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set acc to {} |
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tell mReturn(f) |
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repeat with i from 1 to lng |
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set acc to acc & (|λ|(item i of xs, i, xs)) |
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end repeat |
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end tell |
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if {text, string} contains class of xs then |
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acc as text |
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else |
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acc |
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end if |
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end concatMap |
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-- eq (==) :: Eq a => a -> a -> Bool |
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on eq(a, b) |
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a = b |
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end eq |
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-- foldl :: (a -> b -> a) -> a -> [b] -> a |
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on foldl(f, startValue, xs) |
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tell mReturn(f) |
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set v to startValue |
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set lng to length of xs |
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repeat with i from 1 to lng |
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set v to |λ|(v, item i of xs, i, xs) |
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end repeat |
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return v |
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end tell |
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end foldl |
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-- group :: Eq a => [a] -> [[a]] |
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on group(xs) |
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script eq |
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on |λ|(a, b) |
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a = b |
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end |λ| |
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end script |
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groupBy(eq, xs) |
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end group |
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-- groupBy :: (a -> a -> Bool) -> [a] -> [[a]] |
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on groupBy(f, xs) |
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-- Typical usage: groupBy(on(eq, f), xs) |
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set mf to mReturn(f) |
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script enGroup |
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on |λ|(a, x) |
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if length of (active of a) > 0 then |
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set h to item 1 of active of a |
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else |
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set h to missing value |
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end if |
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if h is not missing value and mf's |λ|(h, x) then |
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{active:(active of a) & {x}, sofar:sofar of a} |
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else |
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{active:{x}, sofar:(sofar of a) & {active of a}} |
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end if |
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end |λ| |
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end script |
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if length of xs > 0 then |
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set dct to foldl(enGroup, {active:{item 1 of xs}, sofar:{}}, rest of xs) |
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if length of (active of dct) > 0 then |
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sofar of dct & {active of dct} |
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else |
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sofar of dct |
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end if |
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else |
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{} |
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end if |
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end groupBy |
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-- map :: (a -> b) -> [a] -> [b] |
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on map(f, xs) |
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-- The list obtained by applying f |
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-- to each element of xs. |
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tell mReturn(f) |
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set lng to length of xs |
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set lst to {} |
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repeat with i from 1 to lng |
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set end of lst to |λ|(item i of xs, i, xs) |
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end repeat |
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return lst |
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end tell |
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end map |
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-- mReturn :: First-class m => (a -> b) -> m (a -> b) |
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on mReturn(f) |
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-- 2nd class handler function lifted into 1st class script wrapper. |
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if script is class of f then |
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f |
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else |
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script |
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property |λ| : f |
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end script |
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end if |
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end mReturn |
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-- sort :: Ord a => [a] -> [a] |
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on sort(xs) |
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((current application's NSArray's arrayWithArray:xs)'s ¬ |
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sortedArrayUsingSelector:"compare:") as list |
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end sort</lang> |
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{{Out}} |
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<pre>{"1", "5", "6", "b", "g", "s", "t", "z"}</pre> |
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=={{header|APL}}== |
=={{header|APL}}== |
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