[Tutor] Recursive permutation

[Eivind Triel]

Hi
 
I am pusling withe a code that makes all the possible permutations of a
string, not only the entire lenght of the string but also len(string) -
1 , -2 etc etc.
 
Like this:
Sting = 123
This give:
['1','2','3','12','13','21','23','31','32','123','132','213','231,'312',
321']
 
Well, I've found this code:
 
#!/usr/bin/python
import sys
 
def tree(txt, result=''):
   if txt:
     for i in range(len(txt)):
       tree(txt[:i] + txt[i+1:], result + txt[i])
   else:
     print result
 
if __name__ == "__main__":
   tree(list(sys.argv[1]))

#Bob Gailer
#bgailer@[...].edu <mailto:#bgailer@[...].edu> 
#303 442 2625
 
Thanx, Bob
 
This code maks a permutation of the entire list (all the 3 digs), but
how do I make the permutations of lower lists?
Going one down i seems easy: Remove alle the element one at a time and
make a permultation of the rest. But going two down - it's like: Remove
[1,2] then [1,3] then [1, ..] then [2,3] then [2,..] then [3,4] then
[3,..] etc etc. 
But what i going n'th down like? It seems to be som kind of combination
but I just can't get i right.
 
Well is there a nice code that will do the trick?
 
-Eivind
 
 
 


-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.python.org/pipermail/tutor/attachments/20041118/d4970a52/attachment.htm