{"id":9065,"date":"2020-01-31T12:04:31","date_gmt":"2020-01-31T04:04:31","guid":{"rendered":"http:\/\/www.zhushiyao.com\/?p=9065"},"modified":"2020-01-31T12:05:28","modified_gmt":"2020-01-31T04:05:28","slug":"98a43c78c0","status":"publish","type":"post","link":"http:\/\/www.zhushiyao.com\/?p=9065","title":{"rendered":"\u8fd9\u4e9b\u65b9\u6cd5\uff0c\u80fd\u591f\u8ba9\u4f60\u7684 Python \u7a0b\u5e8f\u5feb\u5982\u95ea\u7535"},"content":{"rendered":"
\n

\u6765\u6e90\uff1a<\/span>\u673a\u5668\u4e4b\u5fc3<\/span><\/p><\/blockquote>\n

\u8ba8\u538c Python \u7684\u4eba\u603b\u662f\u4f1a\u8bf4\uff0c\u4ed6\u4eec\u4e0d\u60f3\u7528 Python \u7684\u4e00\u4e2a\u91cd\u8981\u539f\u56e0\u662f Python \u5f88\u6162\u3002\u800c\u4e8b\u5b9e\u4e0a\uff0c\u65e0\u8bba\u4f7f\u7528\u4ec0\u4e48\u7f16\u7a0b\u8bed\u8a00\uff0c\u7279\u5b9a\u7a0b\u5e8f\u7684\u8fd0\u884c\u901f\u5ea6\u5f88\u5927\u7a0b\u5ea6\u4e0a\u53d6\u51b3\u4e8e\u7f16\u5199\u7a0b\u5e8f\u7684\u5f00\u53d1\u4eba\u5458\u4ee5\u53ca\u4ed6\u4eec\u4f18\u5316\u7a0b\u5e8f\u3001\u52a0\u5feb\u7a0b\u5e8f\u8fd0\u884c\u901f\u5ea6\u7684\u6280\u80fd\u3002<\/span><\/section>\n
<\/section>\n
\u90a3\u4e48\uff0c\u8ba9\u6211\u4eec\u8bc1\u660e\u90a3\u4e9b\u4eba\u9519\u4e86\uff01\u672c\u6587\u5c06\u4ecb\u7ecd\u5982\u4f55\u63d0\u5347 Python \u7a0b\u5e8f\u7684\u6548\u7387\uff0c\u8ba9\u5b83\u4eec\u8fd0\u884c\u98de\u5feb\uff01<\/span><\/section>\n
<\/section>\n
\"\u8fd9\u4e9b\u65b9\u6cd5\uff0c\u80fd\u591f\u8ba9\u4f60\u7684<\/span><\/section>\n
<\/section>\n
\u8ba1\u65f6\u4e0e\u6027\u80fd\u5206\u6790<\/span><\/strong><\/span><\/section>\n
<\/section>\n
\u5728\u5f00\u59cb\u4f18\u5316\u4e4b\u524d\uff0c\u6211\u4eec\u9996\u5148\u9700\u8981\u627e\u5230\u4ee3\u7801\u7684\u54ea\u4e00\u90e8\u5206\u771f\u6b63\u62d6\u6162\u4e86\u6574\u4e2a\u7a0b\u5e8f\u3002\u6709\u65f6\u7a0b\u5e8f\u6027\u80fd\u7684\u74f6\u9888\u663e\u800c\u6613\u89c1\uff0c\u4f46\u5f53\u4f60\u4e0d\u77e5\u9053\u74f6\u9888\u5728\u4f55\u5904\u65f6\uff0c\u8fd9\u91cc\u6709\u4e00\u4e9b\u5e2e\u52a9\u627e\u5230\u6027\u80fd\u74f6\u9888\u7684\u529e\u6cd5\uff1a<\/span><\/section>\n
<\/section>\n
\u6ce8\uff1a\u4e0b\u5217\u7a0b\u5e8f\u7528\u4f5c\u6f14\u793a\u76ee\u7684\uff0c\u8be5\u7a0b\u5e8f\u8ba1\u7b97 e \u7684 X \u6b21\u65b9\uff08\u6458\u81ea Python \u6587\u6863\uff09\uff1a<\/span><\/section>\n
<\/section>\n
#\u00a0slow_program.py<\/span>
from<\/span>\u00a0decimal\u00a0import<\/span>\u00a0*

def<\/span>\u00a0exp(x)<\/span>:<\/span>
\u00a0\u00a0\u00a0\u00a0getcontext().prec\u00a0+=\u00a02<\/span>
\u00a0\u00a0\u00a0\u00a0i,\u00a0lasts,\u00a0s,\u00a0fact,\u00a0num\u00a0=\u00a00<\/span>,\u00a00<\/span>,\u00a01<\/span>,\u00a01<\/span>,\u00a01<\/span>
while<\/span>\u00a0s\u00a0!=\u00a0lasts:
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0lasts\u00a0=\u00a0s
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0i\u00a0+=\u00a01<\/span>
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0fact\u00a0*=\u00a0i
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0num\u00a0*=\u00a0x
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0s\u00a0+=\u00a0num\u00a0\/\u00a0fact
\u00a0\u00a0\u00a0\u00a0getcontext().prec\u00a0-=\u00a02<\/span>
return<\/span>\u00a0+s

exp(Decimal(150<\/span>))
exp(Decimal(400<\/span>))
exp(Decimal(3000<\/span>))<\/code><\/pre>\n
<\/section>\n
\u6700\u61d2\u60f0\u7684\u300c\u6027\u80fd\u5206\u6790\u300d<\/span><\/strong><\/section>\n
<\/section>\n
\u9996\u5148\uff0c\u6700\u7b80\u5355\u4f46\u8bf4\u5b9e\u8bdd\u4e5f\u5f88\u61d2\u7684\u65b9\u6cd5\u2014\u2014\u4f7f\u7528 Unix \u7684 time \u547d\u4ee4\uff1a<\/span><\/section>\n
<\/section>\n
~\u00a0<\/code><\/pre>\n
<\/pre>\n
nbsp;time\u00a0python3.8<\/span>\u00a0slow_program.py

real<\/span>\u00a0\u00a0\u00a0\u00a00<\/span>m11,058s<\/span>
user\u00a0\u00a0\u00a0\u00a00<\/span>m11,050s<\/span>
sys\u00a0\u00a0\u00a0\u00a0\u00a00<\/span>m0,008s<\/span><\/code><\/pre>\n
<\/section>\n
\u5982\u679c\u4f60\u53ea\u60f3\u7ed9\u6574\u4e2a\u7a0b\u5e8f\u8ba1\u65f6\uff0c\u8fd9\u4e2a\u547d\u4ee4\u5373\u53ef\u5b8c\u6210\u76ee\u7684\uff0c\u4f46\u901a\u5e38\u662f\u4e0d\u591f\u7684\u2026\u2026<\/span><\/section>\n
<\/section>\n
\u6700\u7ec6\u81f4\u7684\u6027\u80fd\u5206\u6790<\/span><\/strong><\/section>\n
<\/section>\n
\u53e6\u4e00\u4e2a\u6781\u7aef\u662f cProfile\uff0c\u5b83\u63d0\u4f9b\u4e86\u300c\u592a\u591a\u300d\u7684\u4fe1\u606f\uff1a<\/span><\/section>\n
<\/section>\n
~\u00a0<\/code><\/pre>\n
<\/pre>\n
nbsp;python3.8<\/span>\u00a0-m\u00a0cProfile\u00a0-s\u00a0time<\/span>\u00a0slow_program.py
1297<\/span>\u00a0function<\/span>\u00a0calls<\/span>\u00a0(1272\u00a0primitive\u00a0calls)<\/span><\/span>\u00a0in<\/span>\u00a011.081<\/span>\u00a0seconds

\u00a0\u00a0\u00a0Ordered\u00a0by:\u00a0internal\u00a0time<\/span>

\u00a0\u00a0\u00a0ncalls\u00a0\u00a0tottime\u00a0\u00a0percall\u00a0\u00a0cumtime\u00a0\u00a0percall\u00a0filename:lineno(function<\/span>)<\/span>
3<\/span>\u00a0\u00a0\u00a011.079<\/span>\u00a0\u00a0\u00a0\u00a03.693<\/span>\u00a0\u00a0\u00a011.079<\/span>\u00a0\u00a0\u00a0\u00a03.693<\/span>\u00a0slow_program.py:4<\/span>(exp<\/span>)
1<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.002<\/span>\u00a0\u00a0\u00a0\u00a00.002<\/span>\u00a0{built-in<\/span>\u00a0method\u00a0_imp.create_dynamic}
4<\/span>\/1<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a011.081<\/span>\u00a0\u00a0\u00a011.081<\/span>\u00a0{built-in<\/span>\u00a0method\u00a0builtins.exec}
6<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0{built-in<\/span>\u00a0method\u00a0__new__\u00a0of\u00a0type<\/span>\u00a0object\u00a0at\u00a00x9d12c0<\/span>}
6<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0abc.py:132<\/span>(__new__)
23<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0_weakrefset.py:36<\/span>(__init__)
245<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0{built-in<\/span>\u00a0method\u00a0builtins.getattr}
2<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0{built-in<\/span>\u00a0method\u00a0marshal.loads}
10<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0<frozen\u00a0importlib._bootstrap_external>:1233<\/span>(find_spec)
8<\/span>\/4<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0abc.py:196<\/span>(__subclasscheck__)
15<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0{built-in<\/span>\u00a0method\u00a0posix.stat}
6<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0{built-in<\/span>\u00a0method\u00a0builtins.__build_class__}
1<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0__init__.py:357<\/span>(namedtuple)
48<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0<frozen\u00a0importlib._bootstrap_external>:57<\/span>(_path_join)
48<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0<frozen\u00a0importlib._bootstrap_external>:59<\/span>(<listcomp>)
1<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a0\u00a00.000<\/span>\u00a0\u00a0\u00a011.081<\/span>\u00a0\u00a0\u00a011.081<\/span>\u00a0slow_program.py:1<\/span>(<module>)
...<\/code><\/pre>\n
<\/section>\n
\u8fd9\u91cc\uff0c\u6211\u4eec\u7ed3\u5408 cProfile \u6a21\u5757\u548c time \u53c2\u6570\u8fd0\u884c\u6d4b\u8bd5\u811a\u672c\uff0c\u4f7f\u8f93\u51fa\u884c\u6309\u7167\u5185\u90e8\u65f6\u95f4\uff08cumtime\uff09\u6392\u5e8f\u3002\u8fd9\u7ed9\u6211\u4eec\u63d0\u4f9b\u4e86\u5927\u91cf\u4fe1\u606f\uff0c\u4e0a\u9762\u4f60\u770b\u5230\u7684\u884c\u53ea\u662f\u5b9e\u9645\u8f93\u51fa\u7684 10%\u3002\u4ece\u8f93\u51fa\u7ed3\u679c\u6211\u4eec\u53ef\u4ee5\u770b\u5230 exp \u51fd\u6570\u662f\u7f6a\u9b41\u7978\u9996\uff08\u60ca\u4e0d\u60ca\u559c\uff0c\u610f\u4e0d\u610f\u5916\uff09\uff0c\u73b0\u5728\u6211\u4eec\u53ef\u4ee5\u66f4\u52a0\u4e13\u6ce8\u4e8e\u8ba1\u65f6\u548c\u6027\u80fd\u5206\u6790\u4e86\u2026\u2026<\/span><\/section>\n
<\/section>\n
\u8ba1\u65f6\u4e13\u7528\u51fd\u6570<\/span><\/strong><\/section>\n
<\/section>\n
\u73b0\u5728\u6211\u4eec\u77e5\u9053\u4e86\u9700\u8981\u5173\u6ce8\u54ea\u91cc\uff0c\u90a3\u4e48\u6211\u4eec\u53ef\u80fd\u53ea\u60f3\u8981\u7ed9\u8fd0\u884c\u7f13\u6162\u7684\u51fd\u6570\u8ba1\u65f6\u800c\u4e0d\u53bb\u7ba1\u4ee3\u7801\u7684\u5176\u4ed6\u90e8\u5206\u3002\u6211\u4eec\u53ef\u4ee5\u4f7f\u7528\u4e00\u4e2a\u7b80\u5355\u7684\u88c5\u9970\u5668\u6765\u505a\u5230\u8fd9\u70b9\uff1a<\/span><\/section>\n
<\/section>\n
def<\/span>\u00a0timeit_wrapper(func)<\/span><\/span>:
\u00a0\u00a0\u00a0\u00a0@wraps(func)
def<\/span>\u00a0wrapper(*args,\u00a0**kwargs)<\/span><\/span>:
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0start\u00a0=\u00a0time.perf_counter()\u00a0\u00a0#\u00a0Alternatively,\u00a0you\u00a0can\u00a0use\u00a0time.process_time()<\/span>
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0func_return_val\u00a0=\u00a0func(*args,\u00a0**kwargs)
end<\/span>\u00a0=\u00a0time.perf_counter()
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0print('{0:<10}.{1:<8}\u00a0:\u00a0{2:<8}'<\/span>.format(func.__module__<\/span>,\u00a0func.__name__<\/span>,\u00a0end<\/span>\u00a0-\u00a0start))
return<\/span>\u00a0func_return_val
return<\/span>\u00a0wrapper<\/code><\/pre>\n
<\/section>\n
\u63a5\u7740\uff0c\u5c06\u8be5\u88c5\u9970\u5668\u6309\u5982\u4e0b\u65b9\u5f0f\u5e94\u7528\u5728\u5f85\u6d4b\u51fd\u6570\u4e0a\uff1a<\/span><\/section>\n
<\/section>\n
@timeit_wrapper
def\u00a0exp<\/span>(x<\/span>):
\u00a0\u00a0\u00a0\u00a0...

print<\/span>('{0:<10}\u00a0{1:<8}\u00a0{2:^8}'<\/span>.format('module'<\/span>,\u00a0'function'<\/span>,\u00a0'time'<\/span>))
exp<\/span>(Decimal(150<\/span>))
exp<\/span>(Decimal(400<\/span>))
exp<\/span>(Decimal(3000<\/span>))<\/code><\/pre>\n
<\/section>\n
\u5f97\u5230\u5982\u4e0b\u8f93\u51fa\uff1a<\/span><\/section>\n
<\/section>\n
~\u00a0<\/code><\/pre>\n
<\/pre>\n
nbsp;python3.8<\/span>\u00a0slow_program.py
module\u00a0\u00a0\u00a0\u00a0\u00a0function<\/span>\u00a0\u00a0\u00a0time<\/span>
__main__\u00a0\u00a0.exp<\/span>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0:\u00a00.003267502994276583<\/span>
__main__\u00a0\u00a0.exp<\/span>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0:\u00a00.038535295985639095<\/span>
__main__\u00a0\u00a0.exp<\/span>\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0:\u00a011.728486061969306<\/span><\/code><\/pre>\n
<\/section>\n
\u6b64\u65f6\u6211\u4eec\u9700\u8981\u8003\u8651\u60f3\u8981\u6d4b\u91cf\u54ea\u4e00\u7c7b\u65f6\u95f4\u3002time \u5e93\u63d0\u4f9b\u4e86 time.perf_counter \u548c time.process_time \u4e24\u79cd\u65f6\u95f4\u3002\u5176\u533a\u522b\u5728\u4e8e\uff0cperf_counter \u8fd4\u56de\u7edd\u5bf9\u503c\uff0c\u5176\u4e2d\u5305\u62ec\u4e86 Python \u7a0b\u5e8f\u5e76\u4e0d\u5728\u8fd0\u884c\u7684\u65f6\u95f4\uff0c\u56e0\u6b64\u5b83\u53ef\u80fd\u53d7\u5230\u673a\u5668\u8d1f\u8f7d\u7684\u5f71\u54cd\u3002\u800c process_time \u53ea\u8fd4\u56de\u7528\u6237\u65f6\u95f4\uff08\u9664\u53bb\u4e86\u7cfb\u7edf\u65f6\u95f4\uff09\uff0c\u4e5f\u5c31\u662f\u53ea\u6709\u8fdb\u7a0b\u8fd0\u884c\u65f6\u95f4\u3002<\/span><\/section>\n
<\/section>\n
\u8ba9\u7a0b\u5e8f\u66f4\u5feb<\/span><\/strong><\/span><\/section>\n
<\/section>\n
\u73b0\u5728\u5230\u4e86\u771f\u6b63\u6709\u8da3\u7684\u90e8\u5206\u4e86\uff0c\u8ba9 Python \u7a0b\u5e8f\u8dd1\u5f97\u66f4\u5feb\uff01\u6211\u4e0d\u4f1a\u544a\u8bc9\u4f60\u4e00\u4e9b\u5947\u6280\u6deb\u5de7\u6216\u4ee3\u7801\u6bb5\u6765\u795e\u5947\u5730\u89e3\u51b3\u7a0b\u5e8f\u7684\u6027\u80fd\u95ee\u9898\uff0c\u800c\u66f4\u591a\u662f\u5173\u4e8e\u901a\u7528\u7684\u60f3\u6cd5\u548c\u7b56\u7565\u3002<\/span>\u4f7f\u7528\u8fd9\u4e9b\u7b56\u7565\uff0c\u53ef\u4ee5\u5bf9\u7a0b\u5e8f\u6027\u80fd\u4ea7\u751f\u5de8\u5927\u7684\u5f71\u54cd\uff0c\u6709\u65f6\u751a\u81f3\u53ef\u4ee5\u5e26\u6765\u9ad8\u8fbe 30% \u7684\u63d0\u901f\u3002<\/span><\/strong><\/section>\n
<\/section>\n
\u4f7f\u7528\u5185\u7f6e\u7684\u6570\u636e\u7c7b\u578b<\/span><\/strong><\/section>\n
<\/section>\n
\u8fd9\u4e00\u70b9\u975e\u5e38\u660e\u663e\u3002\u5185\u7f6e\u7684\u6570\u636e\u7c7b\u578b\u975e\u5e38\u5feb\uff0c\u5c24\u5176\u76f8\u6bd4\u4e8e\u6811\u6216\u94fe\u8868\u7b49\u81ea\u5b9a\u4e49\u7c7b\u578b\u800c\u8a00\u3002\u8fd9\u4e3b\u8981\u662f\u56e0\u4e3a\u5185\u7f6e\u6570\u636e\u7c7b\u578b\u4f7f\u7528 C \u8bed\u8a00\u5b9e\u73b0\uff0c\u4f7f\u7528 Python \u5b9e\u73b0\u7684\u4ee3\u7801\u5728\u8fd0\u884c\u901f\u5ea6\u4e0a\u548c\u5b83\u4eec\u6ca1\u6cd5\u6bd4\u3002<\/span><\/section>\n
<\/section>\n
\u4f7f\u7528 lru_cache \u5b9e\u73b0\u7f13\u5b58\/\u8bb0\u5fc6<\/span><\/strong><\/section>\n
<\/section>\n
\u6211\u5728\u4e4b\u524d\u7684\u535a\u5ba2\u4e2d\u4ecb\u7ecd\u8fc7\u8fd9\u4e00\u6280\u5de7\uff0c\u4f46\u6211\u8ba4\u4e3a\u5b83\u503c\u5f97\u7528\u4e00\u4e2a\u7b80\u5355\u4f8b\u5b50\u518d\u6b21\u8fdb\u884c\u8bf4\u660e\uff1a<\/span><\/section>\n
<\/section>\n
import<\/span>\u00a0functools
import<\/span>\u00a0time

#\u00a0caching\u00a0up\u00a0to\u00a012\u00a0different\u00a0results<\/span>
@functools.lru_cache(maxsize=12)<\/span>
def<\/span>\u00a0slow_func(x)<\/span>:<\/span>
\u00a0\u00a0\u00a0\u00a0time.sleep(2<\/span>)\u00a0\u00a0#\u00a0Simulate\u00a0long\u00a0computation<\/span>
return<\/span>\u00a0x

slow_func(1<\/span>)\u00a0\u00a0#\u00a0...\u00a0waiting\u00a0for\u00a02\u00a0sec\u00a0before\u00a0getting\u00a0result<\/span>
slow_func(1<\/span>)\u00a0\u00a0#\u00a0already\u00a0cached\u00a0-\u00a0result\u00a0returned\u00a0instantaneously!<\/span>

slow_func(3<\/span>)\u00a0\u00a0#\u00a0...\u00a0waiting\u00a0for\u00a02\u00a0sec\u00a0before\u00a0getting\u00a0result<\/span><\/code><\/pre>\n
<\/section>\n
\u4e0a\u9762\u7684\u51fd\u6570\u4f7f\u7528 time.sleep \u6a21\u62df\u4e86\u7e41\u91cd\u7684\u8ba1\u7b97\u8fc7\u7a0b\u3002\u5f53\u6211\u4eec\u7b2c\u4e00\u6b21\u4f7f\u7528\u53c2\u6570 1 \u8c03\u7528\u51fd\u6570\u65f6\uff0c\u5b83\u7b49\u5f85\u4e86 2 \u79d2\u949f\u540e\u8fd4\u56de\u4e86\u7ed3\u679c\u3002\u5f53\u518d\u6b21\u8c03\u7528\u65f6\uff0c\u7ed3\u679c\u5df2\u7ecf\u88ab\u7f13\u5b58\u8d77\u6765\uff0c\u6240\u4ee5\u5b83\u8df3\u8fc7\u4e86\u51fd\u6570\u4f53\uff0c\u76f4\u63a5\u8fd4\u56de\u7ed3\u679c\u3002<\/span><\/section>\n
<\/section>\n
\u4f7f\u7528\u5c40\u90e8\u53d8\u91cf<\/span><\/strong><\/section>\n
<\/section>\n
\u8fd9\u548c\u6bcf\u4e2a\u4f5c\u7528\u57df\u4e2d\u53d8\u91cf\u7684\u67e5\u627e\u901f\u5ea6\u6709\u5173\u3002\u6211\u4e4b\u6240\u4ee5\u8bf4\u300c\u6bcf\u4e2a\u4f5c\u7528\u57df\u300d\uff0c\u662f\u56e0\u4e3a\u8fd9\u4e0d\u4ec5\u4ec5\u5173\u4e4e\u5c40\u90e8\u53d8\u91cf\u6216\u5168\u5c40\u53d8\u91cf\u3002\u4e8b\u5b9e\u4e0a\uff0c\u5c31\u8fde\u51fd\u6570\u4e2d\u7684\u5c40\u90e8\u53d8\u91cf\u3001\u7c7b\u7ea7\u522b\u7684\u5c5e\u6027\u548c\u5168\u5c40\u5bfc\u5165\u51fd\u6570\u8fd9\u4e09\u8005\u7684\u67e5\u627e\u901f\u5ea6\u90fd\u4f1a\u6709\u533a\u522b\u3002\u51fd\u6570\u4e2d\u7684\u5c40\u90e8\u53d8\u91cf\u6700\u5feb\uff0c\u7c7b\u7ea7\u522b\u5c5e\u6027\uff08\u5982 self.name\uff09\u6162\u4e00\u4e9b\uff0c\u5168\u5c40\u5bfc\u5165\u51fd\u6570\uff08\u5982 time.time\uff09\u6700\u6162\u3002<\/span><\/section>\n
<\/section>\n
\u4f60\u53ef\u4ee5\u901a\u8fc7\u8fd9\u79cd\u770b\u4f3c\u6ca1\u6709\u5fc5\u8981\u7684\u4ee3\u7801\u7ec4\u7ec7\u65b9\u5f0f\u6765\u63d0\u9ad8\u6548\u7387\uff1a<\/span><\/section>\n
<\/section>\n
#\u00a0\u00a0Example\u00a0#1<\/span>
class<\/span>\u00a0FastClass<\/span>:<\/span>

def<\/span>\u00a0do_stuff(self)<\/span>:<\/span>
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0temp\u00a0=\u00a0self.value\u00a0\u00a0#\u00a0this\u00a0speeds\u00a0up\u00a0lookup\u00a0in\u00a0loop<\/span>
for<\/span>\u00a0i\u00a0in<\/span>\u00a0range(10000<\/span>):
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0...\u00a0\u00a0#\u00a0Do\u00a0something\u00a0with\u00a0`temp`\u00a0here<\/span>

#\u00a0\u00a0Example\u00a0#2<\/span>
import<\/span>\u00a0random

def<\/span>\u00a0fast_function()<\/span>:<\/span>
\u00a0\u00a0\u00a0\u00a0r\u00a0=\u00a0random.random
for<\/span>\u00a0i\u00a0in<\/span>\u00a0range(10000<\/span>):
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0print(r())\u00a0\u00a0#\u00a0calling\u00a0`r()`\u00a0here,\u00a0is\u00a0faster\u00a0than\u00a0global\u00a0random.random()<\/span>
<\/code><\/pre>\n
\u4f7f\u7528\u51fd\u6570<\/span><\/strong><\/p>\n
\u8fd9\u4e5f\u8bb8\u6709\u4e9b\u53cd\u76f4\u89c9\uff0c\u56e0\u4e3a\u8c03\u7528\u51fd\u6570\u4f1a\u8ba9\u66f4\u591a\u7684\u4e1c\u897f\u5165\u6808\uff0c\u8fdb\u800c\u5728\u51fd\u6570\u8fd4\u56de\u65f6\u4e3a\u7a0b\u5e8f\u5e26\u6765\u8d1f\u62c5\uff0c\u4f46\u8fd9\u5176\u5b9e\u548c\u4e4b\u524d\u7684\u7b56\u7565\u76f8\u5173\u3002\u5982\u679c\u4f60\u53ea\u662f\u628a\u6240\u6709\u4ee3\u7801\u6254\u8fdb\u4e00\u4e2a\u6587\u4ef6\u800c\u6ca1\u6709\u628a\u5b83\u4eec\u653e\u8fdb\u51fd\u6570\uff0c\u90a3\u4e48\u5b83\u4f1a\u56e0\u4e3a\u4f17\u591a\u7684\u5168\u5c40\u53d8\u91cf\u800c\u53d8\u6162\u3002\u56e0\u6b64\uff0c\u4f60\u53ef\u4ee5\u901a\u8fc7\u5c06\u6240\u6709\u4ee3\u7801\u5c01\u88c5\u5728 main \u51fd\u6570\u4e2d\u5e76\u8c03\u7528\u5b83\u6765\u5b9e\u73b0\u52a0\u901f\uff0c\u5982\u4e0b\u6240\u793a\uff1a<\/span><\/section>\n
<\/section>\n
<\/section>\n
def<\/span>\u00a0main()<\/span>:<\/span>
\u00a0\u00a0\u00a0\u00a0...\u00a0\u00a0#\u00a0All\u00a0your\u00a0previously\u00a0global\u00a0code<\/span>

main()<\/code><\/pre>\n
<\/section>\n
\u4e0d\u8981\u8bbf\u95ee\u5c5e\u6027<\/span><\/strong><\/section>\n
<\/section>\n
\u53e6\u4e00\u4e2a\u53ef\u80fd\u8ba9\u7a0b\u5e8f\u53d8\u6162\u7684\u4e1c\u897f\u662f\u7528\u6765\u8bbf\u95ee\u5bf9\u8c61\u5c5e\u6027\u7684\u70b9\u8fd0\u7b97\u7b26\uff08.\uff09\u3002\u8fd9\u4e2a\u8fd0\u7b97\u7b26\u4f1a\u5f15\u8d77\u7a0b\u5e8f\u4f7f\u7528__getattribute__\u8fdb\u884c\u5b57\u5178\u67e5\u627e\uff0c\u8fdb\u800c\u4e3a\u7a0b\u5e8f\u5e26\u6765\u4e0d\u5fc5\u8981\u7684\u5f00\u9500\u3002\u90a3\u4e48\uff0c\u6211\u4eec\u600e\u4e48\u907f\u514d\uff08\u6216\u8005\u9650\u5236\uff09\u4f7f\u7528\u5b83\u5462\uff1f<\/span><\/section>\n
<\/section>\n
<\/section>\n
#\u00a0\u00a0Slow:<\/span>
import<\/span>\u00a0re

def<\/span>\u00a0slow_func()<\/span>:<\/span>
for<\/span>\u00a0i\u00a0in<\/span>\u00a0range(10000<\/span>):
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0re.findall(regex,\u00a0line)\u00a0\u00a0#\u00a0Slow!<\/span>

#\u00a0\u00a0Fast:<\/span>
from<\/span>\u00a0re\u00a0import<\/span>\u00a0findall

def<\/span>\u00a0fast_func()<\/span>:<\/span>
for<\/span>\u00a0i\u00a0in<\/span>\u00a0range(10000<\/span>):
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0findall(regex,\u00a0line)\u00a0\u00a0#\u00a0Faster!<\/span><\/code><\/pre>\n
<\/section>\n
\u5f53\u5fc3\u5b57\u7b26\u4e32<\/span><\/strong><\/section>\n
<\/section>\n
\u5f53\u5728\u5faa\u73af\u4e2d\u4f7f\u7528\u53d6\u6a21\u8fd0\u7b97\u7b26\uff08%s\uff09\u6216 .format() \u65f6\uff0c\u5b57\u7b26\u4e32\u64cd\u4f5c\u4f1a\u53d8\u5f97\u5f88\u6162\u3002\u6709\u6ca1\u6709\u66f4\u597d\u7684\u9009\u62e9\u5462\uff1f\u6839\u636e Raymond Hettinger \u8fd1\u671f\u53d1\u5e03\u7684\u63a8\u6587\uff0c\u6211\u4eec\u53ea\u9700\u8981\u4f7f\u7528 f-string \u5373\u53ef\uff0c\u5b83\u53ef\u8bfb\u6027\u66f4\u5f3a\uff0c\u4ee3\u7801\u66f4\u52a0\u7d27\u51d1\uff0c\u5e76\u4e14\u901f\u5ea6\u66f4\u5feb\uff01\u57fa\u4e8e\u8fd9\u4e00\u89c2\u70b9\uff0c\u5982\u4e0b\u4ece\u5feb\u5230\u6162\u5217\u51fa\u4e86\u4f60\u53ef\u4ee5\u4f7f\u7528\u7684\u4e00\u7cfb\u5217\u65b9\u6cd5\uff1a<\/span><\/section>\n
<\/section>\n
f'{s}<\/span>\u00a0{t}<\/span>'<\/span>\u00a0\u00a0#\u00a0Fast!<\/span>
s\u00a0+\u00a0'\u00a0\u00a0'<\/span>\u00a0+\u00a0t\u00a0
'\u00a0'<\/span>.join((s,\u00a0t))
'%s\u00a0%s'<\/span>\u00a0%\u00a0(s,\u00a0t)\u00a0
'{}\u00a0{}'<\/span>.format(s,\u00a0t)
Template('$s\u00a0$t'<\/span>).substitute(s=s,\u00a0t=t)\u00a0\u00a0#\u00a0Slow!<\/span><\/code><\/pre>\n
<\/section>\n
\u751f\u6210\u5668\u672c\u8d28\u4e0a\u5e76\u4e0d\u4f1a\u66f4\u5feb\uff0c\u56e0\u4e3a\u5b83\u4eec\u7684\u76ee\u7684\u662f\u60f0\u6027\u8ba1\u7b97\uff0c\u4ee5\u8282\u7701\u5185\u5b58\u800c\u975e\u8282\u7701\u65f6\u95f4\u3002\u7136\u800c\uff0c\u8282\u7701\u7684\u5185\u5b58\u4f1a\u8ba9\u7a0b\u5e8f\u8fd0\u884c\u66f4\u5feb\u3002\u4e3a\u4ec0\u4e48\u5462\uff1f\u5982\u679c\u4f60\u6709\u4e00\u4e2a\u5927\u578b\u6570\u636e\u96c6\uff0c\u5e76\u4e14\u4f60\u6ca1\u6709\u4f7f\u7528\u751f\u6210\u5668\uff08\u8fed\u4ee3\u5668\uff09\uff0c\u90a3\u4e48\u6570\u636e\u53ef\u80fd\u9020\u6210 CPU \u7684 L1 \u7f13\u5b58\u6ea2\u51fa\uff0c\u8fdb\u800c\u5bfc\u81f4\u8bbf\u5b58\u901f\u5ea6\u663e\u8457\u53d8\u6162\u3002<\/span><\/section>\n
<\/section>\n
\u5f53\u6d89\u53ca\u5230\u6548\u7387\u65f6\uff0c\u975e\u5e38\u91cd\u8981\u7684\u4e00\u70b9\u662f CPU \u4f1a\u5c06\u5b83\u6b63\u5728\u5904\u7406\u7684\u6570\u636e\u4fdd\u5b58\u5f97\u79bb\u81ea\u5df1\u8d8a\u8fd1\u8d8a\u597d\uff0c\u4e5f\u5c31\u662f\u4fdd\u5b58\u5728\u7f13\u5b58\u4e2d\u3002\u8bfb\u8005\u53ef\u4ee5\u770b\u4e00\u770b Raymond Hettingers \u7684\u6f14\u8bb2\uff08https:\/\/www.youtube.com\/watch?v=OSGv2VnC0go&t=8m17s\uff09\uff0c\u5176\u4e2d\u63d0\u5230\u4e86\u8fd9\u4e9b\u95ee\u9898\u3002<\/span><\/section>\n
<\/section>\n
\u603b\u7ed3<\/strong><\/span><\/section>\n
<\/section>\n
\u4f18\u5316\u7684\u7b2c\u4e00\u8981\u4e49\u5c31\u662f\u300c\u4e0d\u8981\u53bb\u505a\u300d\u3002\u4f46\u5982\u679c\u4f60\u5fc5\u987b\u8981\u505a\uff0c\u6211\u5e0c\u671b\u8fd9\u4e9b\u5c0f\u6280\u5de7\u53ef\u4ee5\u5e2e\u52a9\u5230\u4f60\u3002\u7136\u800c\uff0c\u4f18\u5316\u4ee3\u7801\u65f6\u4e00\u5b9a\u8981\u8c28\u614e\uff0c\u56e0\u4e3a\u8be5\u64cd\u4f5c\u53ef\u80fd\u6700\u7ec8\u9020\u6210\u4ee3\u7801\u53ef\u8bfb\u6027\u53d8\u5dee\u3001\u53ef\u7ef4\u62a4\u6027\u53d8\u5dee\uff0c\u8fd9\u4e9b\u5f0a\u7aef\u53ef\u80fd\u8d85\u8fc7\u4ee3\u7801\u4f18\u5316\u6240\u5e26\u6765\u7684\u597d\u5904\u3002<\/span><\/section>\n
<\/section>\n
\u53c2\u8003\u94fe\u63a5\uff1a<\/span><\/em>https:\/\/towardsdatascience.com\/making-python-programs-blazingly-fast-c1cd79bd1b32<\/span><\/em><\/span><\/section>\n<\/div>\n
\u8f6c\u81ea\uff1ahttps:\/\/mp.weixin.qq.com\/s\/hidWQghW3Gy_ysqGlS5MRA<\/p>\n","protected":false},"excerpt":{"rendered":"
\u6765\u6e90\uff1a\u673a\u5668\u4e4b\u5fc3 \u8ba8\u538c Python \u7684\u4eba\u603b\u662f\u4f1a\u8bf4\uff0c\u4ed6\u4eec\u4e0d\u60f3\u7528 Python \u7684\u4e00\u4e2a\u91cd\u8981\u539f\u56e0\u662f Python \u5f88 … \u7ee7\u7eed\u9605\u8bfb\u201c\u8fd9\u4e9b\u65b9\u6cd5\uff0c\u80fd\u591f\u8ba9\u4f60\u7684 Python \u7a0b\u5e8f\u5feb\u5982\u95ea\u7535\u201d<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[2],"tags":[8,263],"_links":{"self":[{"href":"http:\/\/www.zhushiyao.com\/index.php?rest_route=\/wp\/v2\/posts\/9065"}],"collection":[{"href":"http:\/\/www.zhushiyao.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.zhushiyao.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.zhushiyao.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.zhushiyao.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=9065"}],"version-history":[{"count":2,"href":"http:\/\/www.zhushiyao.com\/index.php?rest_route=\/wp\/v2\/posts\/9065\/revisions"}],"predecessor-version":[{"id":9070,"href":"http:\/\/www.zhushiyao.com\/index.php?rest_route=\/wp\/v2\/posts\/9065\/revisions\/9070"}],"wp:attachment":[{"href":"http:\/\/www.zhushiyao.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=9065"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.zhushiyao.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=9065"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.zhushiyao.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=9065"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}