Sum adjacent elements of a list if their values are equal using list comprehension in python

Question

I am facing this problem where I need to add adjacent elements of a list if their value are equal in Python. Below are my list and expected outcome:

• my_list = [1,1,1,0,0,0,1,1,0,0,0,1,1,0,0,0,1]
• final_list = [3,0,2,0,2,0,1]

Similarly, here is another example:

• my_second_list = [1,1,0,0,0,1,0,0,1]
• expected_outcome= [2,0,1,0,1]

Answer 1

You can use itertools.groupby on an unsorted list:

>>> from itertools import groupby
>>> [sum(group) for _, group in groupby(my_list)]
[3, 0, 2, 0, 2, 0, 1]