Question

If I have a list in python such as:

stuff = [1, 2, 3, 4, 5, 6, 7, 8, 9]

with length n (in this case 9) and I am interested in creating lists of length n/2 (in this case 4). I want all possible sets of n/2 values in the original list, for example:

[1, 2, 3, 4], [2, 3, 4, 5], ..., [9, 1, 2, 3]  

is there some list comprehension code I could use to iterate through the list and retrieve all of those sublists? I don’t care about the order of the values within the lists, I am just trying to find a clever method of generating the lists.

Answer 1

>>> stuff = [1, 2, 3, 4, 5, 6, 7, 8, 9]
>>>
>>> n=len(stuff)
>>>
>>> [(stuff+stuff[:n/2-1])[i:i+n/2] for i in range(n)]
[[1, 2, 3, 4], [2, 3, 4, 5], [3, 4, 5, 6], [4, 5, 6, 7], [5, 6, 7, 8], [6, 7, 8, 9], [7, 8, 9, 1], [8, 9, 1, 2], [9, 1, 2, 3]]
>>>

Note: above code is based on assumption from your example

[1, 2, 3, 4], [2, 3, 4, 5], ..., [9, 1, 2, 3]  

If you really need all possible values, you need to use itertools.permutations or combinations function as others suggested.