I want to split each list of lists into sublists of given length. I have a courses array which looks like this:
[['CS105', 'ENG101', 'MATH101', 'GER', 'ENG102', 'CS230', 'MATH120', 'GER', 'CS205', 'FREE', 'GER', 'CS106', 'CS215', 'CS107', 'ENG204', 'GER', 'MATH220', 'CS300', 'CS206', 'CS306', 'GER', 'FREE', 'CS312', 'CS450', 'GER', 'CS321', 'FREE', 'CS325', 'GER', 'CS322', 'MAJOR', 'CS310', 'STAT205', '', 'CS443', 'CS412', 'CS421', 'GER', 'CS444', 'FREE', 'FREE','','',''], ['CS105', 'ENG101', 'MATH101', 'GER', 'ENG102', 'CS230', 'MATH120', 'GER', 'CS205', 'FREE', 'GER', 'CS106', 'CS215', 'CS107', 'ENG204', 'GER', 'MATH220', 'CS300', 'CS206', 'CS306', 'GER', 'FREE', 'CS312', 'CS450', 'GER', 'CS321', 'FREE', 'CS325', 'GER', 'CS322', 'MAJOR', 'CS310', 'STAT205', '', 'CS443', 'CS412', 'CS421', 'GER', 'CS444', 'FREE', 'FREE','','',''],...]
I want to split each list in sublists in and them to look like this:
[[['CS105', 'ENG101', 'MATH101', 'GER'],['ENG102', 'CS230', 'MATH120', 'GER'], ['CS205', 'FREE'], ['GER'], ['CS106', 'CS215', 'CS107','ENG204', 'GER'], ['MATH220', 'CS300', 'CS206', 'CS306'], ['GER', 'FREE'], ['CS312'], ['CS450', 'GER', 'CS321', 'FREE', 'CS325'], ['GER', 'CS322', 'MAJOR', 'CS310'], ['STAT205',''], [''], ['CS443', 'CS412', 'CS421', 'GER',''], ['CS444', 'FREE', 'FREE',''],['','']]...]
what I have done till now is the following:
schedule = [4, 4, 2, 1, 5, 4, 2, 1, 5, 4, 2, 1, 5, 4, 2, 1]
for i in courses:
Output = [courses[x - y: x] for x, y in zip(accumulate(schedule), schedule)]
print(Output[0])
but what is printed with Output[0] is 4 lists in a row, so as I get it it takes pairs of 4 probably. schedule is the given lengths that I want each list to be splitted. I cannot understand how I need to loop probably in order to achieve the result I need.
Got a working piece of code for you:
new_list = []
for c in courses:
_sum = 0
_list = []
for t in schedule:
el = c[_sum:_sum + t]
_sum += t
_list.append(el)
new_list.append(_list)
Probably can be done quicker but this should do the job!
Write me a message if you got any questions or it is not working properly. Hope I could help.
Here's a function that does what you want:
from itertools import accumulate
def divide_into_schedule(input_list, schedule):
if schedule[0] != 0:
schedule.insert(0, 0)
indices = list(accumulate(schedule))
output_list = [list() for _ in input_list]
for start_index, end_index in zip(indices, indices[1:]):
for input_sublist, output_sublist in zip(input_list, output_list):
output_sublist.append(input_sublist[start_index:end_index])
return output_list
The core idea here is:
schedule
list;indices[1:]
), so that the values become the start and end index to select from each sublist; input_list
and output_list
; input_list
onto output_list
.Call it by passing the input list and schedule as such:
input_list = [['CS105', 'ENG101', 'MATH101', 'GER', 'ENG102', 'CS230', 'MATH120', 'GER', 'CS205', 'FREE', 'GER', 'CS106', 'CS215', 'CS107', 'ENG204', 'GER', 'MATH220', 'CS300', 'CS206', 'CS306', 'GER', 'FREE', 'CS312', 'CS450', 'GER', 'CS321', 'FREE', 'CS325', 'GER', 'CS322', 'MAJOR', 'CS310', 'STAT205', '', 'CS443', 'CS412', 'CS421', 'GER', 'CS444', 'FREE', 'FREE','','',''], ['CS105', 'ENG101', 'MATH101', 'GER', 'ENG102', 'CS230', 'MATH120', 'GER', 'CS205', 'FREE', 'GER', 'CS106', 'CS215', 'CS107', 'ENG204', 'GER', 'MATH220', 'CS300', 'CS206', 'CS306', 'GER', 'FREE', 'CS312', 'CS450', 'GER', 'CS321', 'FREE', 'CS325', 'GER', 'CS322', 'MAJOR', 'CS310', 'STAT205', '', 'CS443', 'CS412', 'CS421', 'GER', 'CS444', 'FREE', 'FREE','','',''],...]
schedule = [4, 4, 2, 1, 5, 4, 2, 1, 5, 4, 2, 1, 5, 4, 2, 1]
output_list = divide_into_schedule(input_list, schedule)
The result isn't exactly the same as your desired output due to the typos I mentioned in my comment, but I believe it does what you want.
Your original idea of using itertools.accumulate
was actually quite good, you just made some small mistakes:
output = [ [sublist[x - y: x] for x, y in zip(accumulate(schedule), schedule)] for sublist in courses ]
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