l_x0 = [item for items in l_x for item in items.split(',') if not '[' in items] # Convert the nested lists to lists. l_x1 = [. i[1:-1].split(',') for i in l_x if '[' in i. ] # Add the two lists. l_x = l_x0 + l_x1. This last solution will work on any list stored as a string, nested or not. More @Wikipedia
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