#149784 - 2005-10-12 05:26 PM
Select a random element from an array
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xpanmanx
Starting to like KiXtart
Registered: 2002-07-08
Posts: 108
Loc: St. Louis MO USA
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Hi, I'm just learning to use arrays and I could use a spot of help.
I'm using Bryce's DirPlus() to build an array of all the files in a directory, then I'm trying to grab a random element of that array.
(I'm using Shawn's Randomize() to seed the RNG.)
I keep getting dinged out with "Error: Error in expression: this type of array not supported in expressions.!"
Will someone please give me a jump-start?
Code:
Break On
$dummy=SetOption('NoVarsInStrings','On')
$dummy=SetOption('Explicit','On')
Dim $FILE_ARRAY,$FILE_ARRAY_ELEMENT,$FILE_PATH
Randomize()
$File_Array=DirPlus('c:\windows\media') ;this directory is an example for the purposes of this post
$File_Array_Element=$File_Array(Rnd(Ubound($File_Array)))
? $File_Array($File_Array_Element) ;this is where the error occurs
Sleep 1
Quit
Here's the DirPlus() code in it's own post - I've not made any changes to the UDF in my script LINK
And here's the Randomize() code LINK
Best regards,
Tim ==
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#149785 - 2005-10-12 05:29 PM
Re: Select a random element from an array
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Richard H.
Administrator
Registered: 2000-01-24
Posts: 4946
Loc: Leatherhead, Surrey, UK
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You need "[]", not "()":
Code:
$File_Array_Element=$File_Array[Rnd(Ubound($File_ARRAY))]
"Random element="+$File_Array_Element ?
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#149786 - 2005-10-12 05:47 PM
Re: Select a random element from an array
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xpanmanx
Starting to like KiXtart
Registered: 2002-07-08
Posts: 108
Loc: St. Louis MO USA
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Thanks, Richard - that took care of the error in fine style.
When running the code below, which is an evolution of my original post, $RANDOM behaves as expected, but $FILE always returns the first file in the directory. Why might this be happening?
Another oddity - it seems that my RND call is simply incrementing on successive executions, rather than generating random output. What's going on there?
Code:
Break On
$dummy=SetOption('NoVarsInStrings','On')
$dummy=SetOption('Explicit','On')
Dim $FILE_ARRAY,$RANDOM,$FILE_ARRAY_ELEMENT,$FILE
Randomize() ;Randomize() @ KiXtart.org - http://tinyurl.com/7ue38
$File_Array=DirPlus('c:\windows\media','/a-d') ;DirPlus() @ KiXtart.org - http://tinyurl.com/83qoy
$Random=Rnd(Ubound($File_Array))
$File_Array_Element=$File_Array[$Random]
$File=$File_Array[$File_Array_Element]
? 'Element=' + $Random
? 'File=' + $File
Sleep 0.5
Quit
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#149787 - 2005-10-12 05:52 PM
Re: Select a random element from an array
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maciep
Korg Regular
Registered: 2002-06-14
Posts: 947
Loc: Pittsburgh
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I think this
Code:
$File_Array_Element=$File_Array[$Random]
$File=$File_Array[$File_Array_Element]
should just be
Code:
$File=$File_Array[$Random]
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#149789 - 2005-10-13 10:32 AM
Re: Select a random element from an array
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Richard H.
Administrator
Registered: 2000-01-24
Posts: 4946
Loc: Leatherhead, Surrey, UK
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Quote:
Yes, thank you very much.
Can anyone comment on why $RANDOM seems to increment, instead of 'randomizing?'
Try discarding the first random number as it is often not at all random.
This is not just an issue with KiXtart, it applies to certain pseudo random number generator algorithms.
Code:
$Random=Rnd() ; Discard first number - not very random!
$Random=Rnd(Ubound($File_Array))
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