{"id":9364,"date":"2024-07-09T22:50:18","date_gmt":"2024-07-09T14:50:18","guid":{"rendered":"\/?p=9364"},"modified":"2024-07-09T22:50:18","modified_gmt":"2024-07-09T14:50:18","slug":"%e5%a6%82%e4%bd%95%e4%bd%bf%e7%94%a8python%e5%86%85%e7%bd%ae%e7%bc%93%e5%ad%98%e8%a3%85%e9%a5%b0%e5%99%a8-lru_cache%ef%bc%8ccache-%e4%b8%8e-cached_property","status":"publish","type":"post","link":"\/?p=9364","title":{"rendered":"\u5982\u4f55\u4f7f\u7528Python\u5185\u7f6e\u7f13\u5b58\u88c5\u9970\u5668: @lru_cache\uff0c@cache \u4e0e @cached_property"},"content":{"rendered":"

1. \u4e3a\u4ec0\u4e48\u9700\u8981\u7f13\u5b58\u6280\u672f\uff1f<\/h3>\n

\u4f7f\u7528\u7f13\u5b58\u662f\u4f18\u5316Python\u7a0b\u5e8f\u901f\u5ea6\u7684\u91cd\u8981\u65b9\u6cd5\u4e4b\u4e00<\/strong>\u3002\u5982\u679c\u4f7f\u7528\u5f97\u5f53\uff0c\u53ef\u4ee5\u5927\u5e45\u51cf\u5c11\u8ba1\u7b97\u8d44\u6e90\u7684\u8d1f\u8f7d\uff0c\u6709\u6548\u52a0\u5feb\u4ee3\u7801\u8fd0\u884c\u901f\u5ea6<\/p>\n

Python \u7684\u5185\u7f6e\u5e93 functools<\/strong> \u6a21\u5757\u9644\u5e26\u4e86@lru_cache\uff0c@cache, @cached_property <\/code>\u88c5\u9970\u5668\uff0c\u4f7f\u7528\u975e\u5e38\u7b80\u4fbf\uff0c\u4e0d\u9700\u8981\u5b89\u88c5\u7b2c3\u65b9\u5e93\uff0c\u4e0d\u9700\u8981 redis \u7b49\u6570\u636e\u5e93\u4fdd\u5b58\u5bf9\u8c61\u7b49\uff0c\u901a\u5e38\u53ea\u9700\u89811\u884c\u4ee3\u7801\uff0c\u5c31\u53ef\u4ee5\u5bf9\u51fd\u6570\u8fd0\u7b97\u7ed3\u679c\u3001\u7c7b\u6210\u5458\u65b9\u6cd5\u8fd0\u7b97\u7ed3\u679c\u8fdb\u884c\u7f13\u5b58\u3002<\/p>\n

\u672c\u6587\u5c06\u4ecb\u7ecd\u8fd93\u79cd\u7f13\u5b58\u5de5\u5177\u7684\u4f7f\u7528\u6b65\u9aa4\u53ca\u5b9e\u4f8b\u3002<\/p>\n

2. @lru_cache<\/code> \u7f13\u5b58\u88c5\u9970\u5668\u7684\u4f7f\u7528<\/h3>\n

@lru_cache \u662f\u6700\u5e38\u89c1\u7684\u7f13\u5b58\u88c5\u9970\u5668\u3002lru_cache<\/code> \u662f\uff1a Last recently used cache<\/code> \u7684\u7b80\u5199\uff0c\u53ef\u4ee5\u5c06\u8be5\u51fd\u6570\u6700\u8fd1\u8c03\u7528\u7684\u8f93\u5165\u53c2\u6570\u4ee5\u53ca\u7ed3\u679c\u8fdb\u884c\u7f13\u5b58\u3002\u5982\u679c\u6709\u65b0\u7684\u8c03\u7528\uff0c\u5148\u68c0\u67e5\u7f13\u5b58\u662f\u5426\u6709\u76f8\u540c\u7684\u8f93\u5165\u53c2\u6570\uff0c\u5982\u679c\u5b58\u5728\uff0c\u5219\u76f4\u63a5\u8fd4\u56de\u5bf9\u5e94\u7ed3\u679c\u3002\u5982\u679c\u662f\u65e0\u53c2\u51fd\u6570\uff0c\u7b2c1\u6b21\u8c03\u7528\u540e\uff0c\u4ee5\u540e\u6bcf\u6b21\u8c03\u7528\uff0c\u76f4\u63a5\u8fd4\u56de\u7f13\u5b58\u7ed3\u679c\u3002<\/p>\n

\u5148\u770b1\u4e2a\u4f8b\u5b50<\/p>\n

from functools import lru_cache\nfrom math import sin\n\n@lru_cache\ndef sin_half(x):\n    print("\u975e\u7f13\u5b58...")\n    return sin(x)\/2\n\nprint('first call result:',sin_half(60))\nprint('second call result:',sin_half(60))<\/code><\/pre>\n
\u4e0a\u4f8b\u4e2d\uff0c\u7b2c1\u6b21\u8fd0\u884c\u51fd\u6570\u540e\uff0clru_cache\u4f1a\u7f13\u5b58\u8c03\u7528\u53c2\u6570\u53ca\u8fd4\u56de\u7ed3\u679c\u3002\u7b2c2\u6b21\u8fd0\u884c\u65f6\uff0clru_cache\u90fd\u4f1a\u68c0\u67e5\u8f93\u5165\uff0c\u53d1\u73b0\u7f13\u5b58\u4e2d\u5b58\u5728\u76f8\u540c\u8f93\u5165\u53c2\u657060\uff0c\u5219\u4ece\u7f13\u5b58\u4e2d\u8fd4\u56de\u7ed3\u679c\u3002\u5982\u679c\u51fd\u6570\u6267\u884c\u7684\u662f\u8ba1\u7b97\u91cf\u5f88\u91cd\u7684\u4efb\u52a1\uff0c\u5bf9\u4e8e\u76f8\u540c\u8f93\u5165\uff0c\u53ef\u4ee5\u660e\u663e\u5730\u8282\u7701\u7cfb\u7edf\u8d44\u6e90\u3002<\/p>\n
\u88c5\u9970\u5668\u53c2\u6570<\/strong><\/p>\n
lru_cache\u9ed8\u8ba4\u4e0d\u6e05\u9664\u7f13\u5b58\u5185\u5bb9\uff0c\u56e0\u6b64\u7f13\u5b58\u4f1a\u65e0\u9650\u589e\u957f\uff0c\u5982\u679c\u7a0b\u5e8f\u662f\u957f\u671f\u8fd0\u884c\u7684\u670d\u52a1\uff0c\u53ef\u80fd\u5b58\u5728\u8017\u5c3d\u5185\u5b58\u7684\u98ce\u9669\u3002 \u56e0\u6b64\uff0c\u5fc5\u987b\u6dfb\u52a01\u4e2amaxsize\u53c2\u6570\uff1a
\n@lru_cache(maxsize) \u7684\u53c2\u6570maxsize \u8868\u793a\u8981\u7f13\u5b58\u7684\u6700\u8fd1\u8c03\u7528\u6b21\u6570.
\n\u5982 @lru_cache(360) \u8868\u793a\uff0c\u53ea\u7f13\u5b58\u6700\u8fd1360\u6b21\u7684\u51fd\u6570\u8c03\u7528\u7ed3\u679c\u3002<\/p>\n
@lru_cache(360)\ndef sin_half(x):\n    return sin(x)\/2<\/code><\/pre>\n
\u7f13\u5b58\u64cd\u4f5c<\/strong><\/p>\n
\u67e5\u770b\u7f13\u5b58\u62a5\u544a: sin_half.cache_info()<\/code>
\n\u5f3a\u5236\u6e05\u9664\u7f13\u5b58\u5185\u5bb9\uff1a sin_half.cache_clear()<\/code>
\n\u5f53\u7136\u4e5f\u53ef\u4ee5\u4f7f\u7528 python\u7684 garbage collection \u6e05\u9664\u7f13\u5b58\u3002<\/p>\n
\u4e0b\u9762\u4f7f\u75281\u4e2a\u793a\u4f8b\u6765\u6f14\u793a\u4e0a\u8ff0\u5185\u5bb9\uff1a<\/p>\n
import functools\nimport gc\n\n# \u4e3b\u8981\u529f\u80fd\uff1a \n# \u9a8c\u8bc1  @lru_cache \u88c5\u9970\u5668\uff0c.chche_info() \u548c .cache_clear() \u65b9\u6cd5\u7684\u4f7f\u7528\n#       garbage collection \u7684\u4f7f\u7528\n\n@functools.lru_cache(maxsize = 300) # Max number of Last recently used cache\ndef fib(n):\n    if n < 2:\n        return n\n    return fib(n-1) + fib(n-2)\n\nfib(30)\nfib.cache_clear()\n\n# Before Clearing\nprint(fib.cache_info())\n\n# After Clearing\nprint(fib.cache_info())\n\n@functools.lru_cache(maxsize = None)\ndef gfg1():\n    # insert function logic here\n    pass\n\n# \u518d\u6b21\u8fd0\u884c\u51fd\u6570 \ngfg1()\nfib(30)\n# garbage collection\ngc.collect()\n\n# All objects collected\nobjects = [i for i in gc.get_objects() \n           if isinstance(i, functools._lru_cache_wrapper)]\n\nprint(gfg1.cache_info())\n\n# All objects cleared\nfor object in objects:\n    object.cache_clear()\n\nprint(gfg1.cache_info())<\/code><\/pre>\n
\u8fd0\u884c\u7a0b\u5ea6\uff0c\u8f93\u51fa\u4e3a\uff1a<\/p>\n
CacheInfo(hits=0, misses=0, maxsize=300, currsize=0)\nCacheInfo(hits=0, misses=0, maxsize=300, currsize=0)\nCacheInfo(hits=0, misses=1, maxsize=None, currsize=1)\nCacheInfo(hits=0, misses=0, maxsize=None, currsize=0)\n1234<\/code><\/pre>\n
3. @cache<\/code> \u7f13\u5b58\u88c5\u9970\u5668\u7684\u4f7f\u7528<\/h3>\n
\u76f8\u6bd4@lru_cache, @cache \u88c5\u9970\u5668\u66f4\u8f7b\u91cf\u5316\uff0c\u901f\u5ea6\u66f4\u5feb\uff0c\u4e14\u662f\u7ebf\u7a0b\u5b89\u5168\uff0c\u4e0d\u540c\u7ebf\u7a0b\u53ef\u4ee5\u8c03\u7528\u540c1\u4e2a\u51fd\u6570\uff0c\u7f13\u5b58\u503c\u53ef\u4ee5\u5171\u4eab\u3002<\/p>\n
import functools\nimport time\n\n@functools.cache\ndef fib(n):\n    if n < 2:\n        return n\n    return fib(n-1) + fib(n-2)\n\nif __name__ == '__main__':\n\n    start_time = time.time()\n    print(fib(400))\n    end_time = time.time()\n    execution_time_without_cache = end_time - start_time\n    print("Time taken without cache: {:.8f} seconds".format(execution_time_without_cache))\n\n    start_time = time.time()\n    print(fib(400))\n    end_time = time.time()\n    execution_time_without_cache = end_time - start_time\n    print("Time taken with cache: {:.8f} seconds".format(execution_time_without_cache))    <\/code><\/pre>\n
output:<\/p>\n
176023680645013966468226945392411250770384383304492191886725992896575345044216019675\nTime taken without cache: 0.00095391 seconds\n176023680645013966468226945392411250770384383304492191886725992896575345044216019675\nTime taken with cache: 0.00000000 seconds<\/code><\/pre>\n
4. @cached_property<\/code> \u7f13\u5b58\u88c5\u9970\u5668\u7684\u4f7f\u7528<\/h3>\n
@cached_property<\/code>\u662f\u4e00\u4e2a\u88c5\u9970\u5668\uff0c\u5b83\u5c06\u7c7b\u7684\u65b9\u6cd5\u8f6c\u6362\u4e3a\u5c5e\u6027\uff0c\u5176\u503c\u4ec5\u8ba1\u7b97\u4e00\u6b21\uff0c\u7136\u540e\u7f13\u5b58\u4e3a\u666e\u901a\u5c5e\u6027\u3002\u56e0\u6b64\uff0c\u53ea\u8981\u5b9e\u4f8b\u6301\u4e45\u5b58\u5728\uff0c\u7f13\u5b58\u7684\u7ed3\u679c\u5c31\u53ef\u7528\uff0c\u6211\u4eec\u53ef\u4ee5\u5c06\u8be5\u65b9\u6cd5\u7528\u4f5c\u7c7b\u7684\u5c5e\u6027\u90a3\u6837\u6765\u4f7f\u7528\uff0c\u5982<\/p>\n
\u8c03\u7528\uff1a    : instance.method\n\u53d6\u4ee3\u65e7\u65b9\u5f0f : instance.method()<\/code><\/pre>\n
@cached_property<\/code>\u662f Python \u4e2d functools\u6a21\u5757\u7684\u4e00\u90e8\u5206\u3002\u5b83\u7c7b\u4f3c\u4e8e property\uff08\uff09<\/code>\uff0c\u4f46 @cached_property<\/code> \u5e26\u6709\u4e00\u4e2a\u989d\u5916\u7684\u529f\u80fd\uff0c\u90a3\u5c31\u662f\u7f13\u5b58\u3002<\/p>\n
\u4f46\u662f\u5b83\u5982\u4f55\u51cf\u5c11\u6267\u884c\u65f6\u95f4\u5e76\u4f7f\u7a0b\u5e8f\u66f4\u5feb\uff1f\u8bf7\u8003\u8651\u4ee5\u4e0b\u793a\u4f8b\uff1a<\/p>\n
# Without using @cached_property\n\n# A sample class\nclass Sample():\n\n    def __init__(self, lst):\n    self.long_list = lst\n\n    # a method to find the sum of the\n    # given long list of integer values\n    def find_sum(self):\n        return (sum(self.long_list))\n\n# obj is an instance of the class sample\n# the list can be longer, this is just\n# an example\nobj = Sample([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])\nprint(obj.find_sum())\nprint(obj.find_sum())\nprint(obj.find_sum())<\/code><\/pre>\n
\u8f93\u51fa\u4e3a\uff1a<\/p>\n
55\n55\n55<\/code><\/pre>\n
\u5728\u8fd9\u91cc\uff0c\u5047\u8bbe\u5982\u679c\u6211\u4eec\u4f20\u90121\u4e2a\u957f\u5217\u8868\uff0c\u6bcf\u6b21\u8c03\u7528 find_sum()\u65b9\u6cd5\u65f6\u90fd\u4f1a\u8ba1\u7b97\u7ed9\u5b9a\u5217\u8868\u7684\u603b\u548c\uff0c\u4ece\u800c\u82b1\u8d39\u5927\u91cf\u65f6\u95f4\u8fd0\u884c\uff0c\u7a0b\u5e8f\u6700\u7ec8\u4f1a\u53d8\u6162\u3002\u6211\u4eec\u60f3\u8981\u7684\u662f\uff0c\u7531\u4e8e\u5217\u8868\u5728\u521b\u5efa\u5b9e\u4f8b\u540e\u4e0d\u4f1a\u66f4\u6539\uff0c\u56e0\u6b64\uff0c\u5982\u679c\u5217\u8868\u7684\u603b\u548c\u53ea\u8ba1\u7b97\u4e00\u6b21\uff0c\u800c\u4e0d\u662f\u6bcf\u6b21\u5728\u6211\u4eec\u8c03\u7528\u65b9\u6cd5\u5e76\u5e0c\u671b\u8bbf\u95ee\u603b\u548c\u65f6\u8ba1\u7b97\uff0c\u90a3\u5c31\u592a\u597d\u4e86\u3002\u8fd9\u53ef\u4ee5\u901a\u8fc7\u4f7f\u7528@cached_property\u6765\u5b9e\u73b0,<\/p>\n
# With using @cached_property\n\nfrom functools import cached_property\n\n# A sample class\nclass Sample():\n    def __init__(self, lst):\n    self.long_list = lst\n\n    # a method to find the sum of the\n    # given long list of integer values\n    @cached_property\n    def find_sum(self):\n        return (sum(self.long_list))\n\n# obj is an instance of the class sample\nobj = Sample([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])\nprint(obj.find_sum)\nprint(obj.find_sum)\nprint(obj.find_sum)<\/code><\/pre>\n
\u4f7f\u7528\u4e86@cached_property\u88c5\u9970\u5668\u540e\uff0c\u65e0\u987b\u91cd\u65b0\u8ba1\u7b97\uff0c\u603b\u662f\u7acb\u5373\u8fd4\u56defind_sum\u503c\u3002
\n\u5982\u679c\u9700\u8981\u91cd\u65b0\u8ba1\u7b97\u5c5e\u6027\uff0c\u5219\u5220\u9664\u8be5\u5c5e\u6027\u5373\u53ef\uff0c\u4e0b\u6b21\u8c03\u7528\u4f1a\u91cd\u65b0\u8ba1\u7b97\uff0c\u5728\u672c\u4f8b \u4e2d\u6dfb\u52a0\u5982\u4e0b\u8bed\u53e5\uff0c<\/p>\n
del obj.find_sum\nobj.long_list = range(20,30)\nprint(obj.find_sum)<\/code><\/pre>\n
\u8fd0\u884c\u4ee3\u7801\uff0c\u8f93\u51fa\u7ed3\u679c\u4e3a\uff1a<\/p>\n
55\n55\n55\n245<\/code><\/pre>\n
5. \u5404\u79cd\u7f13\u5b58\u65b9\u6cd5\u7684\u9002\u7528\u573a\u666f<\/h3>\n
\u7efc\u4e0a\u6240\u8ff0\uff0c\u5efa\u8bae\u5982\u4e0b\uff1a
\n1\uff09 \u5982\u679c\u7a0b\u5e8f\u89c4\u6a21\u5c0f\uff0c\u6216\u591a\u7ebf\u7a0b\u7f16\u7a0b\u65f6\uff0c\u53ef\u4f7f\u7528@cache \u88c5\u9970\u5668\u3002
\n2\uff09 \u5982\u679c\u7a0b\u5ea6\u89c4\u6a21\u5927\uff0c\u5e76\u4e14\u662f\u957f\u65f6\u95f4\u8fd0\u884c\uff0c\u5efa\u8bae\u4f7f\u7528@lru_cache \u88c5\u9970\u5668\uff0c\u4f7f\u7528\u65b9\u6cd5\u7075\u6d3b\uff0c\u4f46\u8981\u6ce8\u610f\u63a7\u5236\u7f13\u5b58\u6570\u91cf\uff0c\u5fc5\u8981\u65f6\u624b\u5de5\u6e05\u7406\u3002
\n3\uff09 \u7f16\u5199\u7c7b\u4ee3\u7801\u65f6\uff0c\u5982\u9700\u5c06\u67d0\u9879\u590d\u6742\u8fd0\u7b97\u7ed3\u679c\u50cf\u5c5e\u6027\u90a3\u6837\u8bbf\u95ee\u65f6\uff0c\u4f7f\u7528@cached_property\u88c5\u9970\u5668\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
1. \u4e3a\u4ec0\u4e48\u9700\u8981\u7f13\u5b58\u6280\u672f\uff1f \u4f7f\u7528\u7f13\u5b58\u662f\u4f18\u5316Python\u7a0b\u5e8f\u901f\u5ea6\u7684\u91cd\u8981\u65b9\u6cd5\u4e4b\u4e00\u3002\u5982\u679c\u4f7f\u7528\u5f97\u5f53\uff0c\u53ef\u4ee5\u5927\u5e45\u51cf\u5c11\u8ba1\u7b97\u8d44\u6e90\u7684\u8d1f\u8f7d\uff0c\u6709\u6548\u52a0\u5feb\u4ee3\u7801\u8fd0\u884c   \u2026 …<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0},"categories":[34],"tags":[],"_links":{"self":[{"href":"\/index.php?rest_route=\/wp\/v2\/posts\/9364"}],"collection":[{"href":"\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=9364"}],"version-history":[{"count":1,"href":"\/index.php?rest_route=\/wp\/v2\/posts\/9364\/revisions"}],"predecessor-version":[{"id":9365,"href":"\/index.php?rest_route=\/wp\/v2\/posts\/9364\/revisions\/9365"}],"wp:attachment":[{"href":"\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=9364"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=9364"},{"taxonomy":"post_tag","embeddable":true,"href":"\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=9364"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}