Question

I have a python list with binary information having either a sequence of 1s or a sequence of 0s for example:

event = [0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1]

How can I store the index values of the starting 1 and ending 1?

For example:

if event = [0, 0, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1] then result = [2,5,8,11]

EDIT2 i realised that result should ideally be result_start=[2,8] result_end=[5,11], like lazyr solution, this way we understand where just a single 1 located. eg. event=[0,0,1,1,0,1], would yield a wrong list for the last 1. Thanks for trying all!

EDIT1: I need the index of the first and the last 1 but first to the last 1.

I tried to code it like the following:

k=False
j=0
result=[]
for i in event:
   if i==1:
       k=True
       result.append(k)
   else:
       k=False      

Answer 1

event = [0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 1,
    1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1]
from itertools import izip_longest

def pair_iterator(event):
    event = [0] + event
    return enumerate(izip_longest(event, event[1:], fillvalue=0), -1)

def one_ranges(event):
    start = [i + 1 for i, pair in pair_iterator(event) if pair == (0, 1)]
    end = [i for i, pair in pair_iterator(event) if pair == (1, 0)]
    return zip(start, end)

print one_ranges(event)

EDIT:

Also find range that starts at index 0.

Created one_ranges function which returns a list of (start, end) tuples.