I have the following two lists
list_1 = [3, 5, 7, 2]
list_2 = [
'1-CHA', '2-NOF', '3-INC',
'4-CHA', '5-NOF', '6-NOF', '7-INC', '8-INC',
'9-INC', '10-INC', '11-CHA', '12-NOF', '13-CHA', '14-CHA', '15-INC',
'16-INC', '17-INC'
]
I want to combine the two lists in the following way:
final_list = [
'1-CHA|2-NOF|3-INC',
'4-CHA|5-NOF|6-NOF|7-INC|8-INC',
'9-INC|10-INC|11-CHA|12-NOF|13-CHA|14-CHA|15-INC',
'16-INC|17-INC'
]
final_list - should have the same length as list_1
You can create an iterator from list_2 so that you can fetch items from the list for the number of times specified in list_1 by calling next on the iterator:
seq = iter(list_2)
final_list = ['|'.join(next(seq) for _ in range(n)) for n in list_1]
You can also use itertools.islice instead to avoid repeated calls to next (thanks to @gog for the suggestion):
from itertools import islice
seq = iter(list_2)
final_list = ['|'.join(islice(seq, 0, n)) for n in list_1]
To do it without using list comprehension or generator expression, you can create an empty list and append items to it:
seq = iter(list_2)
final_list = []
for n in list_1:
items = []
for _ in range(n):
items.append(next(seq))
final_list.append('|'.join(items))