Python appending lists vs adding lists

demo.py

from timeit import Timer
from itertools import islice
from itertools import cycle


def add_list_small(target, source):
    target += source


def add_list_large(target, source):
    target += source


def append_list_small_single(target, source):
    target.append(source[0])


def append_list_large_single(target, source):
    target.append(source[0])


def append_list_small_multi(target, source):
    map(target.append, source)
    # for item in source:
    #     target.append(item)


def append_list_large_multi(target, source):
    map(target.append, source)
    # for item in source:
    #     target.append(item)


if __name__ == "__main__":
    list_small = list(islice(cycle('abcdef'), 20))
    list_large = list(islice(cycle('abcdef'), 20000))
    source_list_small = ['1']
    source_list_large = list(islice(cycle('lmnopqrstuv'), 500))

    print('-------- Small Lists ---------')

    for func in add_list_small, append_list_small_single:
        stmt = '{0.__name__}(list_small, source_list_small)'.format(func)
        setup = "from __main__ import add_list_small, append_list_small_single, list_small, source_list_small"
        print func.__name__, min(Timer(stmt, setup).repeat(50, 1000))

    for func in add_list_large, append_list_large_single:
        stmt = '{0.__name__}(list_large, source_list_small)'.format(func)
        setup = "from __main__ import add_list_large, append_list_large_single, list_large, source_list_small"
        print func.__name__, min(Timer(stmt, setup).repeat(50, 1000))

    print('\n-------- Large Lists ---------')

    for func in add_list_small, append_list_small_multi:
        stmt = '{0.__name__}(list_small, source_list_large)'.format(func)
        setup = "from __main__ import add_list_small, append_list_small_multi, list_small, source_list_large"
        print func.__name__, min(Timer(stmt, setup).repeat(50, 1000))

    for func in add_list_large, append_list_large_multi:
        stmt = '{0.__name__}(list_large, source_list_large)'.format(func)
        setup = "from __main__ import add_list_large, append_list_large_multi, list_large, source_list_large"
        print func.__name__, min(Timer(stmt, setup).repeat(50, 1000))

-------- Small Lists ---------
add_list_small 0.000310897827148
append_list_small_single 0.000353097915649
add_list_large 0.000298023223877
append_list_large_single 0.000354051589966

-------- Large Lists ---------
add_list_small 0.0023410320282
append_list_small_multi 0.0300941467285
add_list_large 0.00239205360413
append_list_large_multi 0.0299570560455
[Finished in 4.6s]