from itertools import combinations
from more_itertools import consume
k = 170
index_list = [16, 32, 48, 62, 76, 88, 100, 110, 120, 128, 136, 142, 148, 153, 158, 161, 164, 166]
for n in range(1, k+1):
iterable = combinations(range(k), n)
for output in iterable:
print(output)
I am having iterables and a list containing indexes as shown above: The index_list is representing intervals: they go from 0 to 16, from 17 to 32, from 33 to 48 and so on. Last interval is 167 to k-1. When I loop a iterable, I want to skip multiple steps, whenever there are 2 values of the output within the same interval. Output (0, 1), for example: Both values are within the interval 0-16, so next output shall be (0, 17). The outputs afterwards would be (0, 18), (0, 19),..., (0, k-1) as these are not within a interval. Afterwards, the output will be (1, 2) which shall be skipped again and so on. And later, when the output is (17, 18) it shall skip to (17, 33). When n is 3, the very first output is (0, 1, 2) which then shall be skipped to (0, 17, 33). The consume-method provided by more-itertools allows one to step multiple elements ahead. Here it would be used like so:
consume(iterable, 20) # skipping 20 steps ahead
I have managed it to get the wanted behavior for 2 elements in the output:
steps = 0
for i, out in enumerate(output):
for j, index in enumerate(index_list):
if out <= index:
break
try:
if output[i + 1] <= index_list[j]:
steps = steps + index_list[j] - output[i + 1]
except:
pass
consume(iterable, steps)
But for 3 elements and more the amount of steps is not calculated correctly anymore. It must be multiplied by some value but I don't know where to get it. Another task is, that I do not want to check for the intervals for every single output. When a consume was executed, it somehow must already know when the next consume-instruction will happen. Any help please?
This code only works when n < 20 (Because the number of statically nested blocks in Python is limited to 20)
k = 170
index_list = [16, 32, 48, 62, 76, 88, 100, 110, 120, 128, 136, 142, 148, 153, 158, 161, 164, 166]
def get_bound(x):
for i in range(len(index_list)):
if x <= index_list[i]:
return index_list[i]
return k
def valid_combs(i, n=None, comb=None):
n = n if n is not None else i
comb = comb or list(range(n))
if i == n:
for x in range(k):
comb[0] = x
yield from valid_combs(i - 1, n, comb)
elif i >= 1:
prev = comb[n - i - 1]
bound = get_bound(prev)
for x in list(range(bound + 1, k)):
comb[n - i] = x
yield from valid_combs(i - 1, n, comb)
else:
yield tuple(comb)
for n in range(1, k+1):
iterable = valid_combs(n)
for output in iterable:
print(output)