Elegant and Fast
Inspired by DanSalmo's comment, here is a solution that is concise, elegant, and at the same time is one of the fastest solutions.
good_set = set(goodvals)good, bad = [], []for item in my_list: good.append(item) if item in good_set else bad.append(item)Tip: Turning goodvals into a set gives us an easy speed boost.
Fastest
For maximum speed, we take the fastest answer and turbocharge it by turning good_list into a set. That alone gives us a 40%+ speed boost, and we end up with a solution that is more than 5.5x as fast as the slowest solution, even while it remains readable.
good_list_set = set(good_list) # 40%+ faster than a tuple.good, bad = [], []for item in my_origin_list: if item in good_list_set: good.append(item) else: bad.append(item)A little shorter
This is a more concise version of the previous answer.
good_list_set = set(good_list) # 40%+ faster than a tuple.good, bad = [], []for item in my_origin_list: out = good if item in good_list_set else bad out.append(item)Elegance can be somewhat subjective, but some of the Rube Goldberg style solutions that are cute and ingenious are quite concerning and should not be used in production code in any language, let alone python which is elegant at heart.
Benchmark results:
filter_BJHomer 80/s -- -3265% -5312% -5900% -6262% -7273% -7363% -8051% -8162% -8244%zip_Funky 118/s 4848% -- -3040% -3913% -4450% -5951% -6085% -7106% -7271% -7393%two_lst_tuple_JohnLaRoy 170/s 11332% 4367% -- -1254% -2026% -4182% -4375% -5842% -6079% -6254%if_else_DBR 195/s 14392% 6428% 1434% -- -882% -3348% -3568% -5246% -5516% -5717%two_lst_compr_Parand 213/s 16750% 8016% 2540% 967% -- -2705% -2946% -4786% -5083% -5303%if_else_1_line_DanSalmo 292/s 26668% 14696% 7189% 5033% 3707% -- -331% -2853% -3260% -3562%tuple_if_else 302/s 27923% 15542% 7778% 5548% 4177% 343% -- -2609% -3029% -3341%set_1_line 409/s 41308% 24556% 14053% 11035% 9181% 3993% 3529% -- -569% -991%set_shorter 434/s 44401% 26640% 15503% 12303% 10337% 4836% 4345% 603% -- -448%set_if_else 454/s 46952% 28358% 16699% 13349% 11290% 5532% 5018% 1100% 469% --The full benchmark code for Python 3.7 (modified from FunkySayu):
good_list = ['.jpg','.jpeg','.gif','.bmp','.png']import randomimport stringmy_origin_list = []for i in range(10000): fname = ''.join(random.choice(string.ascii_lowercase) for i in range(random.randrange(10))) if random.getrandbits(1): fext = random.choice(list(good_list)) else: fext = "." +''.join(random.choice(string.ascii_lowercase) for i in range(3)) my_origin_list.append((fname + fext, random.randrange(1000), fext))# Paranddef two_lst_compr_Parand(*_): return [e for e in my_origin_list if e[2] in good_list], [e for e in my_origin_list if not e[2] in good_list]# dbrdef if_else_DBR(*_): a, b = list(), list() for e in my_origin_list: if e[2] in good_list: a.append(e) else: b.append(e) return a, b# John La Rooydef two_lst_tuple_JohnLaRoy(*_): a, b = list(), list() for e in my_origin_list: (b, a)[e[2] in good_list].append(e) return a, b# # Ants Aasma# def f4():# l1, l2 = tee((e[2] in good_list, e) for e in my_origin_list)# return [i for p, i in l1 if p], [i for p, i in l2 if not p]# My personal way to dodef zip_Funky(*_): a, b = zip(*[(e, None) if e[2] in good_list else (None, e) for e in my_origin_list]) return list(filter(None, a)), list(filter(None, b))# BJ Homerdef filter_BJHomer(*_): return list(filter(lambda e: e[2] in good_list, my_origin_list)), list(filter(lambda e: not e[2] in good_list, my_origin_list))# ChaimG's answer; as a list.def if_else_1_line_DanSalmo(*_): good, bad = [], [] for e in my_origin_list: _ = good.append(e) if e[2] in good_list else bad.append(e) return good, bad# ChaimG's answer; as a set.def set_1_line(*_): good_list_set = set(good_list) good, bad = [], [] for e in my_origin_list: _ = good.append(e) if e[2] in good_list_set else bad.append(e) return good, bad# ChaimG set and if else list.def set_shorter(*_): good_list_set = set(good_list) good, bad = [], [] for e in my_origin_list: out = good if e[2] in good_list_set else bad out.append(e) return good, bad# ChaimG's best answer; if else as a set.def set_if_else(*_): good_list_set = set(good_list) good, bad = [], [] for e in my_origin_list: if e[2] in good_list_set: good.append(e) else: bad.append(e) return good, bad# ChaimG's best answer; if else as a set.def tuple_if_else(*_): good_list_tuple = tuple(good_list) good, bad = [], [] for e in my_origin_list: if e[2] in good_list_tuple: good.append(e) else: bad.append(e) return good, baddef cmpthese(n=0, functions=None): results = {} for func_name in functions: args = ['%s(range(256))' % func_name, 'from __main__ import %s' % func_name] t = Timer(*args) results[func_name] = 1 / (t.timeit(number=n) / n) # passes/sec functions_sorted = sorted(functions, key=results.__getitem__) for f in functions_sorted: diff = [] for func in functions_sorted: if func == f: diff.append("--") else: diff.append(f"{results[f]/results[func]*100 - 100:5.0%}") diffs = " ".join(f'{x:>8s}' for x in diff) print(f"{f:27s} \t{results[f]:,.0f}/s {diffs}")if __name__=='__main__': from timeit import Timercmpthese(1000, 'two_lst_compr_Parand if_else_DBR two_lst_tuple_JohnLaRoy zip_Funky filter_BJHomer if_else_1_line_DanSalmo set_1_line set_if_else tuple_if_else set_shorter'.split(" "))