get_data = itemgetter(*indexes)

line_as_list = line.split(",")
data = list(get_data(line_as_list))

# Change the elements in the list "data"

line_as_list[index1] = data[0]
line_as_list[index2] = data[1]
...

itemsetter(line_as_list, data, indexes)

>>> big=[1,2,3,4]
>>> small=[1.5, 1.7]
>>> big[2:2]
[]
>>> big[2:2]=small
>>> big
[1, 2, 1.5, 1.7, 3, 4]

>>> big=[1,2,3,4]
>>> small=[1.5, 1.7]
>>> big[2:3]=small
>>> big
[1, 2, 1.5, 1.7, 4]