python:split a list of strings into multiple lists before a certain value

February 18, 2022

I have a list as follows,

my_list = ['France, the weather is nice', 'the house is beautiful', 'we have a fresh start here','France, the dinner is amazing', 'the lady is lovely', 'France, the house is beautiful','the location is fascinating']

I want to split the list into multiple list every time the word ‘France,’ is in the string, so the output should be,

desired_list = [['France, the weather is nice', 'the house is beautiful', 'we have a fresh start here'],['France, the dinner is amazing', 'the lady is lovely'],['France, the house is beautiful','the location is fascinating']]

I have tried the following, but would like to keep the sentence that has ‘France,’ too.

new_list =[list(y) for x, y in itertools.groupby(my_list, lambda z: z.startswith('France,)) if not x]

another answer

in addition to the answer given by Titouan L, I also found the answer using more_itertools

import more_itertools as miter
print(list(miter.split_before(my_list, lambda x: x.startswith("France,"))))

>Solution :

I’ve come up with a solution with nested loops, as I’m not very experienced with list comprehension and lambda expression.

my_list = ['France, the weather is nice', 'the house is beautiful', 'we have a fresh start here', 'France, the dinner is amazing',
           'the lady is lovely', 'France, the house is beautiful', 'the location is fascinating']

new_list = []
sub_list = []
for i in my_list:
    if i.startswith('France,'):
        if sub_list != []:
            new_list.append(sub_list)
            sub_list=[]

    sub_list.append(i)
new_list.append(sub_list)