# [Numpy-discussion] lists of zeros and ones

Joe Kington jkington at wisc.edu
Fri Mar 19 11:21:19 EDT 2010

```I just realized that permutations isn't quite what you want, as swapping the
first "1" for the second "1" gives the same thing.  You can use set to get
the unique permutations.
e.g.
In [4]: set(itertools.permutations([1,1,0,0]))
Out[4]:
set([(0, 0, 1, 1),
(0, 1, 0, 1),
(0, 1, 1, 0),
(1, 0, 0, 1),
(1, 0, 1, 0),
(1, 1, 0, 0)])

On Fri, Mar 19, 2010 at 10:17 AM, Joe Kington <jkington at wisc.edu> wrote:

> See itertools.permutations (python standard library)
>
> e.g.
> In [3]: list(itertools.permutations([1,1,0,0]))
> Out[3]:
> [(1, 1, 0, 0),
>  (1, 1, 0, 0),
>  (1, 0, 1, 0),
>  (1, 0, 0, 1),
>  (1, 0, 1, 0),
>  (1, 0, 0, 1),
>  (1, 1, 0, 0),
>  (1, 1, 0, 0),
>  (1, 0, 1, 0),
>  (1, 0, 0, 1),
>  (1, 0, 1, 0),
>  (1, 0, 0, 1),
>  (0, 1, 1, 0),
>  (0, 1, 0, 1),
>  (0, 1, 1, 0),
>  (0, 1, 0, 1),
>  (0, 0, 1, 1),
>  (0, 0, 1, 1),
>  (0, 1, 1, 0),
>  (0, 1, 0, 1),
>  (0, 1, 1, 0),
>  (0, 1, 0, 1),
>
>
>
>  (0, 0, 1, 1),
>  (0, 0, 1, 1)]
>
> Hope that helps,
> -Joe
>
> On Fri, Mar 19, 2010 at 9:53 AM, gerardob <gberbeglia at gmail.com> wrote:
>
>>
>> Hello, i would like to produce lists of lists 1's and 0's.
>>
>> For example, to produce the list composed of:
>>
>> L = [[1,0,0,0],[0,1,0,0],[0,0,1,0],[0,0,0,1]]
>>
>> I just need to do the following:
>>
>> n=4
>> numpy.eye(n,dtype=int).tolist()
>>
>> I would like to know a simple way to generate a list containing all the
>> lists having two 1's at each element.
>>
>> Example, n = 4
>> L2 = [[1,1,0,0],[1,0,1,0],[1,0,0,1],[0,1,1,0],[0,1,0,1],[0,0,1,1]]
>>
>> Any ideas?
>> Thanks.
>>
>>
>>
>>
>>
>>
>>
>> --
>> View this message in context:
>> http://old.nabble.com/lists-of-zeros-and-ones-tp27950978p27950978.html
>> Sent from the Numpy-discussion mailing list archive at Nabble.com.
>>
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>
>
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