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Python | Splitting list on empty string
  • Last Updated : 01 Jul, 2020

Sometimes, we may face an issue in which we require to split a list to list of list on the blank character sent as deliminator. This kind of problem can be used to send messages or can be used in cases where it is desired to have list of list of native list. Let’s discuss certain ways in which this can be done.

Method #1 : Using index() and list slicing
The list slicing can be used to get the sublists from the native list and index function can be used to check for the empty string which can potentially act as a separator. The drawback of this is that it only works for a single split i.e can only divide a list to 2 sublists.




# Python3 code to demonstrate
# divide list to siblist on deliminator
# using index() + list slicing 
  
# initializing list 
test_list = ['Geeks', 'for', '', 'Geeks', 1, 2]
  
# printing original list
print("The original list : " + str(test_list))
  
# using index() + list slicing
# divide list to siblist on deliminator
temp_idx = test_list.index('')
res = [test_list[: temp_idx], test_list[temp_idx + 1: ]]
  
# print result
print("The list of sublist after separation : " + str(res))
Output :

The original list : [‘Geeks’, ‘for’, ”, ‘Geeks’, 1, 2]
The list of sublist after separation : [[‘Geeks’, ‘for’], [‘Geeks’, 1, 2]]

 



Method #2 : Using itertools.groupby() + list comprehension
The problem of the above proposed method can be solved using the groupby function which could divide on all the list breaks given by the empty strings.




# Python3 code to demonstrate
# divide list to siblist on deliminator
# using itertools.groupby() + list comprehension
from itertools import groupby
  
# initializing list 
test_list = ['Geeks', '', 'for', '', 4, 5, '',
                  'Geeks', 'CS', '', 'Portal']
  
# printing original list
print("The original list : " + str(test_list))
  
# using itertools.groupby() + list comprehension
# divide list to siblist on deliminator
res = [list(sub) for ele, sub in groupby(test_list, key = bool) if ele]
  
# print result
print("The list of sublist after separation : " + str(res))
Output :

The original list : [‘Geeks’, ”, ‘for’, ”, 4, 5, ”, ‘Geeks’, ‘CS’, ”, ‘Portal’]
The list of sublist after separation : [[‘Geeks’], [‘for’], [4, 5], [‘Geeks’, ‘CS’], [‘Portal’]]

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