python - Split a list into chunks determined by a separator

Question

I have this list (python):

[[item1],[item2],[item3],[/],[item4],[item5],[item6],[/]...]

I want to separate these into chunks and the elements that will go into each chunk are the elements before the separator "/".

So my chunks would look like:

chunk1 = [[item1],[item2],[item3]]
chunk2 = [[item4],[item5],[item6]]

I've tried and tried, nothing efficient came to mind. Tried looping through it with a for and and if element[x] == '/' then get some positions. It's very dirty and doesn't properly work.

Any help would be appreciated.

Answer 1

The usual approach for collecting contiguous chunks is to use itertools.groupby, for example:

>>> from itertools import groupby
>>> blist = ['item1', 'item2', 'item3', '/', 'item4', 'item5', 'item6', '/']
>>> chunks = (list(g) for k,g in groupby(blist, key=lambda x: x != '/') if k)
>>> for chunk in chunks:
...     print(chunk)
...     
['item1', 'item2', 'item3']
['item4', 'item5', 'item6']

(Your representation of your list [item1],[item2],[item3],[/], makes it look like each of your elements in the list is actually a list, in which case the same approach will work, you simply need to compare against ['/'] or whatever your separator is.)