Python: Equivalent of str.split() for a list of strings - ExecutionTimeTest

setup1="""
s_lines = \
["Action1,A,200,5",
"Phase1,B,100,1,2000",
"Action1,C,300,5",
"Phase2,B,100,1,500",
"Action1,C,400,5",
"Action2,C,10,5",
"Action3,C,10,5"]

s_expected_output = \
    [["Action1,A,200,5"],
    ["Action1,C,300,5"],
    ["Action1,C,400,5", "Action2,C,10,5", "Action3,C,10,5"]]

def split_listofstrings_bysubstring(s_list: list, substring: str, delim_type='contains') -> list:

    split_list=list()
    split_list.append(list())

    if delim_type == 'contains':
        for line in s_list:
            if substring in line and len(split_list[-1])!=0: # current line is delimiter
                split_list.append(list())  # instantiate new sublist
                continue
            split_list[-1].append(line)

    if delim_type == 'startswith':
        for line in s_list:
            if line.startswith(substring) and len(split_list[-1])!=0: # current line is delimiter
                split_list.append(list())  # instantiate new sublist
                continue
            split_list[-1].append(line)

    elif delim_type == 'endswith':
        for line in s_list:
            if line.endswith(substring) and len(split_list[-1])!=0: # current line is delimiter
                split_list.append(list())  # instantiate new sublist
                continue
            split_list[-1].append(line)

    else:
        raise ValueError(f"Parameter passed to delim_type was not recognised. Passed: {delim_type}")

    return split_list
"""


test1 = "split_listofstrings_bysubstring(s_lines, substring = 'Phase', delim_type='startswith')"

setup2 = """
s_lines = \
["Action1,A,200,5",
"Phase1,B,100,1,2000",
"Action1,C,300,5",
"Phase2,B,100,1,500",
"Action1,C,400,5",
"Action2,C,10,5",
"Action3,C,10,5"]

s_expected_output = \
    [["Action1,A,200,5"],
    ["Action1,C,300,5"],
    ["Action1,C,400,5", "Action2,C,10,5", "Action3,C,10,5"]]

from itertools import groupby
class GroupbyHelper(object):

    def __init__(self, val):
        self.val = val
        self.i = 0

    def __call__(self, val):
        self.i += (self.val in val)
        return self.i

def split_listofstrings_bysubstring_groupby(s_list: list, substring: str) -> list:
    return [list(g) for k, g in groupby(s_list, key=GroupbyHelper(substring))]

substring = 'Phase'"""

test2 = """
s_lines_split = split_listofstrings_bysubstring_groupby(s_lines, substring)
s_lines_split_clean = list()
for line in s_lines_split:
    if substring in line[0]:
        s_lines_split_clean.append(line[1:])
    else:
        s_lines_split_clean.append(line)"""

import timeit
# from prefixed import Float

loop = int(1E6)

result = timeit.timeit(test1, setup=setup1, number=loop)
result_1 = result
# print(f"{Float(result/ loop):.2h}s per loop")

result = timeit.timeit(test2, setup=setup2, number=loop)
# print(f"{Float(result/ loop):.2h}s per loop")
result_2 = result

result = timeit.timeit(test2, setup=setup2, number=loop)
# print(f"{Float(result/ loop):.2h}s per loop")
result_2 += result

result = timeit.timeit(test1, setup=setup1, number=loop)
# print(f"{Float(result/ loop):.2h}s per loop")
result_1 += result

print(f"{result_2/result_1:.2%}")