Re: permutation algorithm

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JRS: In article <Oo4mQHdnFHA.3316@xxxxxxxxxxxxxxxxxxxx>, dated Wed, 10
Aug 2005 12:34:50, seen in news:microsoft.public.scripting.vbscript,
Roland Hall <nobody@nowhere.?> posted :
>"Dr John Stockton" wrote in message
>news:YMD6vyARkl9CFwJ9@xxxxxxxxxxxxxxxxxxxxx
>: JRS: In article <#NxvSqlmFHA.2904@xxxxxxxxxxxxxxxxxxxx>, dated Sat, 6
>: Aug 2005 02:43:41, seen in news:microsoft.public.scripting.vbscript,
>: Roland Hall <nobody@nowhere.?> posted :
>:
>: >I'm not sure what type of permutation should would be but I'm trying to
>get
>: >all possible combinations of a string.
>:
>: Combinations are not permutations (in my English).
>
>Sorry to hear that.

You'll see the appropriate usage on the cited page. In a combination,
order does not matter; in a permutation, it does.

>: You can, no doubt, translate the code visible and demonstrated in
>: <URL:http://www.merlyn.demon.co.uk/js-tests.htm#CP>; it could do with
>: independent verification. You'll want to use .split() on your string as
>: a start.
>
>That doesn't work in vbscript.

Use .split() *before* translating to VBScript, so that in the
translation it too is translated <G>.

>: The general approach is to write a function that selects whatever is
>: possible as the first character then calls itself to deal with what is
>: left.
>
>I'm actually looking for the word declining combinations, instead of just
>characters, which y sakuda was so helpful in providing. However, I'm always
>willing to see other possibilities.

The code works on the elements of an array S, which can be whatever
Objects one chooses; characters have an obvious advantage for
convenience of collection and brevity of display. For non-characters,
the expression z+a[j] should be changed to build the result into an
array rather than a string. In the paragraph you quoted, I should have
used 'entity' or 'object' rather than 'character'.

>The j(ava)script routine on your site puts a single comma in the beginning
>and also ends with one. Shouldn't they only be found within the result?

If you mean that after the comma-separated list of items there was
another comma, that's merely an artefact of the previous crude provision
for display.

Change D = "" to D = [] & D += z + "," to D[D.length] = z .

Thanks for causing the thought. D has also been made non-global.

--
© John Stockton, Surrey, UK. ?@merlyn.demon.co.uk Turnpike v4.00 IE 4 ©
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