[Tutor] permutations?

[Steven D'Aprano]

Alex Hall wrote:
> Hi all,
> I am wondering if there is a python package that will find
> permutations? 

What version of Python are you using?

Starting from Python 2.6, the itertools module contains combinations, 
permutations and Cartesian product:

 >>> list(itertools.combinations([1,2,3], 1))
[(1,), (2,), (3,)]
 >>> list(itertools.combinations([1,2,3], 2))
[(1, 2), (1, 3), (2, 3)]
 >>> list(itertools.combinations([1,2,3], 3))
[(1, 2, 3)]

 >>> list(itertools.permutations([1,2,3], 1))
[(1,), (2,), (3,)]
 >>> list(itertools.permutations([1,2,3], 2))
[(1, 2), (1, 3), (2, 1), (2, 3), (3, 1), (3, 2)]
 >>> list(itertools.permutations([1,2,3], 3))
[(1, 2, 3), (1, 3, 2), (2, 1, 3), (2, 3, 1), (3, 1, 2), (3, 2, 1)]

 >>> list(itertools.product([1,2,3], 'ab'))
[(1, 'a'), (1, 'b'), (2, 'a'), (2, 'b'), (3, 'a'), (3, 'b')]


For example, if I have (1, 2, 3), the possibilities I
> want are:
> 12
> 13
> 23
> 123
> 132
> 231
> 
> Order does not matter; 

According to your example, it certainly does -- you have 123 and 132 and 
231 listed as three distinct possibilities.



-- 
Steven