The 2**n different lists that you are seeking have a direct association to the binary representation of the integers 0 through (2**n)-1. You can use this fact and the "repeated division method" for converting numbers between different bases to generate these lists and form the desired list of lists:
def bit_list_maker(n):
x = 2**n
solution_set = []
for i in range(x):
this_answer = []
while i>0:
this_answer.append(i%2)
i=i/2
while len(this_answer)<n:
this_answer.append(0)
this_answer.reverse()
solution_set.append(this_answer)
return solution_set
*
*
Another fun way to do it is to build up the lists recursively. The
possibilities for n bits can be built from the possibilities for n-1 bits by
adding a 1 and a 0 to each possibility (ending up with twice as many
elements):
def recursive_bit_list(n):
if n==1:
return [[0],[1]]
else:
return map(lambda x: x+[0], recursive_bit_list(n-1)) + \
map(lambda x: x+[1], recursive_bit_list(n-1))
Hope this helps!
-Hugh
On 6/14/07, Andy Cheesman <[EMAIL PROTECTED] > wrote:
Hi people
I am trying to generate an array of all possible combinations of 1, and
zeros (see example data) for a rather nice Kinetic mote Carlo program
which I am writing python. So far, I've been working out for
combinations for 4 or less species by hand as it is quick! but I am
looking to automate the process so I can compute combinations for large
numbers of possible species.
I could automate the generation of the array by the use of multiple
loops but that doesn't seem rather pythonic. I was wondering if anyone
had any sensible suggestions or pointers for efficient mechanisms for
the array.
Many Thanks
Andy
Example Data
3 species
array([[1, 1, 1],
[1, 1, 0],
[1, 0, 1],
[0, 1, 1],
[1, 0, 0],
[0, 1, 0],
[0, 0, 1],
[0, 0, 0]])
4 species
array([[1, 1, 1, 1],
[0, 1, 1, 1],
[1, 0, 1, 1],
[1, 1, 0, 1],
[1, 1, 1, 0],
[1, 1, 0, 0],
[1, 0, 1, 0],
[1, 0, 0, 1],
[0, 1, 1, 0],
[0, 1, 0, 1],
[0, 0, 1, 1],
[1, 0, 0, 0],
[0, 1, 0, 0],
[0, 0, 1, 0],
[0, 0, 0, 1],
[0, 0, 0, 0]])
_______________________________________________
Tutor maillist - Tutor@python.org
http://mail.python.org/mailman/listinfo/tutor
_______________________________________________ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
