Lets assume I've got a list of integers:
mylist = [101, 102, 103, 104, 105, 106]
Now I need to create every possible sublist division (order preserved):
sublists = [([101], [102, 103, 104, 105, 106]),
([101, 102], [103, 104, 105, 106]),
([101, 102, 103], [104, 105, 106]),
...
([101, 102], [103, 104], [105, 106]),
...
([101], [102, 103, 104], [105], [106]),
...
([101], [102], [103], [104], [105], [106])]
Any idea? Would itertools be helpful?
You are creating slice points; are you slicing after the current element or not. You can generate these with booleans:
from itertools import product
def sublists(lst):
for doslice in product([True, False], repeat=len(lst) - 1):
slices = []
start = 0
for i, slicehere in enumerate(doslice, 1):
if slicehere:
slices.append(lst[start:i])
start = i
slices.append(lst[start:])
yield slices
Demo:
>>> from pprint import pprint
>>> mylist = [101, 102, 103, 104, 105, 106]
>>> pprint(list(sublists(mylist)))
[[[101], [102], [103], [104], [105], [106]],
[[101], [102], [103], [104], [105, 106]],
[[101], [102], [103], [104, 105], [106]],
[[101], [102], [103], [104, 105, 106]],
[[101], [102], [103, 104], [105], [106]],
[[101], [102], [103, 104], [105, 106]],
[[101], [102], [103, 104, 105], [106]],
[[101], [102], [103, 104, 105, 106]],
[[101], [102, 103], [104], [105], [106]],
[[101], [102, 103], [104], [105, 106]],
[[101], [102, 103], [104, 105], [106]],
[[101], [102, 103], [104, 105, 106]],
[[101], [102, 103, 104], [105], [106]],
[[101], [102, 103, 104], [105, 106]],
[[101], [102, 103, 104, 105], [106]],
[[101], [102, 103, 104, 105, 106]],
[[101, 102], [103], [104], [105], [106]],
[[101, 102], [103], [104], [105, 106]],
[[101, 102], [103], [104, 105], [106]],
[[101, 102], [103], [104, 105, 106]],
[[101, 102], [103, 104], [105], [106]],
[[101, 102], [103, 104], [105, 106]],
[[101, 102], [103, 104, 105], [106]],
[[101, 102], [103, 104, 105, 106]],
[[101, 102, 103], [104], [105], [106]],
[[101, 102, 103], [104], [105, 106]],
[[101, 102, 103], [104, 105], [106]],
[[101, 102, 103], [104, 105, 106]],
[[101, 102, 103, 104], [105], [106]],
[[101, 102, 103, 104], [105, 106]],
[[101, 102, 103, 104, 105], [106]],
[[101, 102, 103, 104, 105, 106]]]
If you want to drop the last entry (containing a list with only one list in it, in turn containing all elements), replace the last 2 lines with:
if start:
slices.append(lst[start:])
yield slices
This is an interesting question! Although Martijn has given an elegant answer, I'd still like to post mine that tackles this problem from another angle - Divide & Conquer:
def sublist_gen(ls):
n = len(ls)
if n == 1:
yield [ls]
else:
for left in sublist_gen(ls[0:n/2]):
for right in sublist_gen(ls[n/2:n]):
yield left + right
yield left[0:-1] + [left[-1] + right[0]] + right[1:]
mylist = [101, 102, 103, 104, 105, 106]
for sublist in sublist_gen(mylist):
print(sublist)
Result:
[[101], [102], [103], [104], [105], [106]]
[[101], [102], [103, 104], [105], [106]]
[[101], [102], [103], [104, 105], [106]]
[[101], [102], [103, 104, 105], [106]]
[[101], [102], [103], [104], [105, 106]]
[[101], [102], [103, 104], [105, 106]]
[[101], [102], [103], [104, 105, 106]]
[[101], [102], [103, 104, 105, 106]]
[[101, 102], [103], [104], [105], [106]]
[[101, 102], [103, 104], [105], [106]]
[[101, 102], [103], [104, 105], [106]]
[[101, 102], [103, 104, 105], [106]]
[[101, 102], [103], [104], [105, 106]]
[[101, 102], [103, 104], [105, 106]]
[[101, 102], [103], [104, 105, 106]]
[[101, 102], [103, 104, 105, 106]]
[[101], [102, 103], [104], [105], [106]]
[[101], [102, 103, 104], [105], [106]]
[[101], [102, 103], [104, 105], [106]]
[[101], [102, 103, 104, 105], [106]]
[[101], [102, 103], [104], [105, 106]]
[[101], [102, 103, 104], [105, 106]]
[[101], [102, 103], [104, 105, 106]]
[[101], [102, 103, 104, 105, 106]]
[[101, 102, 103], [104], [105], [106]]
[[101, 102, 103, 104], [105], [106]]
[[101, 102, 103], [104, 105], [106]]
[[101, 102, 103, 104, 105], [106]]
[[101, 102, 103], [104], [105, 106]]
[[101, 102, 103, 104], [105, 106]]
[[101, 102, 103], [104, 105, 106]]
[[101, 102, 103, 104, 105, 106]]
