What is the best approach to this issue related to cumulative sum per section?-CodePudding

I have this information:
[0,1,1,1,1,1,0,1,1,1,0,1,1,1,1,0,1,1,1]

and need add successively 15 only in the section between zeros, as result:
[0,15,30,45,60,75,0,15,30,45,0,15,30,45,60,0,15,30,45]

CodePudding user response：

import numpy
l = np.array([0,1,1,1,1,1,0,1,1,1,0,1,1,1,1,0,1,1,1])
l *= 15
s = np.hstack([np.cumsum(v) for v in np.split(l, np.where(l==0)[0])])
print(s)

np.split takes an array to be split, and an iterable of cuts. np.where gives you all of the indices i where l[i] == 0. np.cumsum does the cumulative sum on all of these, and then np.hstack puts them all back together.

CodePudding user response：

Pseudo code

create an empty list which will be the result
initialize a counter at 0
for each element of the original list
    add 1 to the counter if the element is not 0 else reset the counter to 0
    append to the result list 15 times the counter