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02.12.2012 19:50:00 • Categories: Applescript • Tags: Applescript

AppleScript: optimizing loops

(* Loop optimizing Example 1 *)
set MyList to {}
repeat 10000 times
    set the end of MyList to " hello from the loop"
end repeat
return MyList as text
-- 5.63s
set MyString to ""
repeat 10000 times
    set MyString to MyString & " hello from the loop"
end repeat
-- 3.71s

(* Loop optimizing Example 2 for complete overview.
* For speed testing you have to split this example in two separate files
*)
(* 

slow version
*)
--create a list to work with
set MyList to {}

--put 5000 elements in the list for us to walk through for testing
repeat with i from 0 to 5000
    set the end of MyList to i
end repeat
--now walk the list again and add up all the number
set MyTotal to 0
repeat with ThisValue in MyList
    set MyTotal to MyTotal + ThisValue
end repeat
--return MyTotal
--2.87s
(*

fast version
*)
--create a global scope list to work with
property MyGlobalList : {}

--make sure it's empty as these are persistent between runs
set MyGlobalList to {}
--now work with a reference to that global list
set MyList2 to a reference to MyGlobalList
--put 5000 elements in the list for us to walk through for testing
repeat with i from 0 to 5000
    set the end of MyList2 to i
end repeat
--now walk the list again and add up all the number
set MyTotal2 to 0
repeat with ThisValue in MyList2
    set MyTotal2 to MyTotal2 + ThisValue
end repeat
--return MyTotal2
--0.09s !!!

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