Check if a Python list has X number of consecutive values equal to Y

I have a collection of lists each containing 16 items, and I want to find lists with 12 consecutive values either > or < than a specified threshold. For now, I have iterated through the lists and put 1 for values greater and -1 for values less than the threshold, and I used to following to eliminate those that don’t have 12 of either.

if list.count(-1) >= 12 or list.count(1) >= 12:

How do I efficiently check for 12 consecutive values? (12 values can loop around) for example this would count

[1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1]

Currently I have 2 nested for loops, but I know this checks the same value multiple times.

                    for i in range(16):
                        light = 0
                        dark = 0
                        for j in range(12):
                            index = i + j
                            if index > 15:
                                index -= 15
                            if list[index] == 1:
                                light += 1
                            elif list[index] == -1:
                                dark += 1
                            else:
                                break
                            if dark > 0 and light > 0:
                                break
                        if dark == 12 or light == 12:
                            return True

Answer

I would harness itertools.groupby following way

import itertools
data = [1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1]
runs = [len(list(g)) for _,g in itertools.groupby(data)]
if data[0] == data[-1]:
    runs[0] += runs.pop()
print(max(runs) >= 12)  # True

Explanation: I use itertools.groupby to get length of runs (in this case [7,4,5]) – itertools.groupby does group only adjacent equal elements, then if first and last values of data are equal I extract last element from runs and add it to first element (as you allow wraparound), then I check if longest run is equal or greater 12.