Steve Wampler wrote:
> Steve Graham wrote:
>
>>I'm looking for a way to generate every possible combination of n letters out
>>of a total of m letters.
>>
>>For example, if the available letters are A, B, C and I want to generate all
>>possible 2-letter combinations, it should generate the following:
>>AB
>>BA
>>AC
>>CA
>>BC
>>CB
>>
>>I think I've seen a trivial way of doing this in Icon/Unicon but don't
>>remember. Any ideas?
>
>
> Hi Steve,
>
> There's a method comp(s, n) in the IPL (procs/strings.icn) that does what you
> want. The
> code is:
>
> procedure comb(s, i) #: character combinations
> local j
>
> if i < 1 then fail
> suspend if i = 1 then !s
> else s[j := 1 to *s - i + 1] || comb(s[j + 1:0], i - 1)
>
> end
Actually, in reading your mail again, I think you mean 'permutations', not
combinations. The following code should work:
procedure permute(s, i)
local j
if i < 1 then fail
suspend if i = 1 then !s
else s[j := 1 to *s] || permute(s[1+:j-1]||s[j+1:0], i-1)
end
--
Steve Wampler -- [EMAIL PROTECTED]
The gods that smiled on your birth are now laughing out loud.
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