{"id":1138552,"date":"2025-01-08T22:01:04","date_gmt":"2025-01-08T14:01:04","guid":{"rendered":"https:\/\/docs.pingcode.com\/ask\/ask-ask\/1138552.html"},"modified":"2025-01-08T22:01:08","modified_gmt":"2025-01-08T14:01:08","slug":"python%e5%a6%82%e4%bd%95%e7%bb%9f%e8%ae%a1%e5%88%97%e8%a1%a8%e4%b8%ad%e6%9f%90%e4%b8%80%e9%a1%b9%e4%b8%aa%e6%95%b0","status":"publish","type":"post","link":"https:\/\/docs.pingcode.com\/ask\/1138552.html","title":{"rendered":"python\u5982\u4f55\u7edf\u8ba1\u5217\u8868\u4e2d\u67d0\u4e00\u9879\u4e2a\u6570"},"content":{"rendered":"

\"python\u5982\u4f55\u7edf\u8ba1\u5217\u8868\u4e2d\u67d0\u4e00\u9879\u4e2a\u6570\"<\/p>\n

\u4f7f\u7528Python\u7edf\u8ba1\u5217\u8868\u4e2d\u67d0\u4e00\u9879\u4e2a\u6570\uff0c\u53ef\u4ee5\u91c7\u7528\u591a\u79cd\u65b9\u6cd5\uff0c\u5982count()\u65b9\u6cd5\u3001collections\u6a21\u5757\u4e2d\u7684Counter\u7c7b\u3001\u4ee5\u53ca\u81ea\u5b9a\u4e49\u51fd\u6570\u7b49\u3002<\/strong>\u5176\u4e2d\uff0c\u6700\u7b80\u5355\u548c\u5e38\u7528\u7684\u65b9\u6cd5\u662f\u4f7f\u7528\u5217\u8868\u7684\u5185\u7f6e\u65b9\u6cd5count()\uff0c\u5b83\u53ef\u4ee5\u76f4\u63a5\u7edf\u8ba1\u67d0\u4e2a\u5143\u7d20\u5728\u5217\u8868\u4e2d\u51fa\u73b0\u7684\u6b21\u6570\u3002\u672c\u6587\u5c06\u8be6\u7ec6\u4ecb\u7ecd\u8fd9\u4e9b\u65b9\u6cd5\uff0c\u5e76\u63d0\u4f9b\u5177\u4f53\u7684\u4ee3\u7801\u793a\u4f8b\u3002<\/p>\n<\/p>\n

\u4e00\u3001\u4f7f\u7528count()\u65b9\u6cd5<\/h3>\n<\/p>\n

count()\u662fPython\u5217\u8868\u5185\u7f6e\u7684\u65b9\u6cd5\uff0c\u53ef\u4ee5\u76f4\u63a5\u7edf\u8ba1\u67d0\u4e2a\u5143\u7d20\u5728\u5217\u8868\u4e2d\u51fa\u73b0\u7684\u6b21\u6570\u3002\u8fd9\u4e2a\u65b9\u6cd5\u975e\u5e38\u7b80\u5355\u6613\u7528\uff0c\u9002\u5408\u7edd\u5927\u591a\u6570\u7684\u7edf\u8ba1\u9700\u6c42\u3002<\/p>\n<\/p>\n

# \u793a\u4f8b\u4ee3\u7801<\/p>\n
my_list = [1, 2, 3, 2, 2, 4, 2, 5]<\/p>\n
element = 2<\/p>\n
count = my_list.count(element)<\/p>\n
print(f"\u5143\u7d20{element}\u5728\u5217\u8868\u4e2d\u51fa\u73b0\u4e86{count}\u6b21")<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4f18\u70b9<\/strong>\uff1acount()\u65b9\u6cd5\u76f4\u89c2\u3001\u7b80\u5355\uff0c\u9002\u5408\u521d\u5b66\u8005\u3002<\/p>\n<\/p>\n
\u7f3a\u70b9<\/strong>\uff1a\u5bf9\u4e8e\u975e\u5e38\u5927\u7684\u5217\u8868\uff0ccount()\u65b9\u6cd5\u7684\u6548\u7387\u53ef\u80fd\u4e0d\u5982\u4e00\u4e9b\u5176\u4ed6\u65b9\u6cd5\u3002<\/p>\n<\/p>\n
\u4e8c\u3001\u4f7f\u7528collections.Counter<\/h3>\n<\/p>\n
collections\u6a21\u5757\u4e2d\u7684Counter\u7c7b\u63d0\u4f9b\u4e86\u4e00\u79cd\u9ad8\u6548\u7684\u65b9\u6cd5\u6765\u7edf\u8ba1\u5217\u8868\u4e2d\u5404\u5143\u7d20\u7684\u51fa\u73b0\u6b21\u6570\u3002Counter\u5bf9\u8c61\u53ef\u4ee5\u7528\u6765\u5feb\u901f\u83b7\u53d6\u67d0\u4e2a\u5143\u7d20\u7684\u8ba1\u6570\uff0c\u5e76\u4e14\u53ef\u4ee5\u5904\u7406\u66f4\u52a0\u590d\u6742\u7684\u7edf\u8ba1\u9700\u6c42\u3002<\/p>\n<\/p>\n
from collections import Counter<\/p>\n
\u793a\u4f8b\u4ee3\u7801<\/strong><\/h2>\n
my_list = [1, 2, 3, 2, 2, 4, 2, 5]<\/p>\n
counter = Counter(my_list)<\/p>\n
element = 2<\/p>\n
count = counter[element]<\/p>\n
print(f"\u5143\u7d20{element}\u5728\u5217\u8868\u4e2d\u51fa\u73b0\u4e86{count}\u6b21")<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4f18\u70b9<\/strong>\uff1aCounter\u7c7b\u4e0d\u4ec5\u53ef\u4ee5\u7edf\u8ba1\u5355\u4e2a\u5143\u7d20\uff0c\u8fd8\u53ef\u4ee5\u7edf\u8ba1\u6574\u4e2a\u5217\u8868\u4e2d\u6240\u6709\u5143\u7d20\u7684\u51fa\u73b0\u6b21\u6570\uff0c\u9002\u5408\u66f4\u590d\u6742\u7684\u7edf\u8ba1\u9700\u6c42\u3002<\/p>\n<\/p>\n
\u7f3a\u70b9<\/strong>\uff1a\u76f8\u5bf9\u4e8ecount()\u65b9\u6cd5\uff0c\u4ee3\u7801\u7a0d\u663e\u590d\u6742\u3002<\/p>\n<\/p>\n
\u4e09\u3001\u4f7f\u7528\u5faa\u73af\u548c\u6761\u4ef6\u5224\u65ad<\/h3>\n<\/p>\n
\u901a\u8fc7\u5faa\u73af\u548c\u6761\u4ef6\u5224\u65ad\u53ef\u4ee5\u624b\u52a8\u7edf\u8ba1\u67d0\u4e2a\u5143\u7d20\u5728\u5217\u8868\u4e2d\u51fa\u73b0\u7684\u6b21\u6570\u3002\u867d\u7136\u8fd9\u79cd\u65b9\u6cd5\u76f8\u5bf9\u7e41\u7410\uff0c\u4f46\u53ef\u4ee5\u63d0\u4f9b\u66f4\u5927\u7684\u7075\u6d3b\u6027\u3002<\/p>\n<\/p>\n
# \u793a\u4f8b\u4ee3\u7801<\/p>\n
my_list = [1, 2, 3, 2, 2, 4, 2, 5]<\/p>\n
element = 2<\/p>\n
count = 0<\/p>\n
for item in my_list:<\/p>\n
    if item == element:<\/p>\n
        count += 1<\/p>\n
print(f"\u5143\u7d20{element}\u5728\u5217\u8868\u4e2d\u51fa\u73b0\u4e86{count}\u6b21")<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4f18\u70b9<\/strong>\uff1a\u7075\u6d3b\uff0c\u53ef\u4ee5\u6839\u636e\u9700\u6c42\u8fdb\u884c\u6269\u5c55\u3002<\/p>\n<\/p>\n
\u7f3a\u70b9<\/strong>\uff1a\u4ee3\u7801\u76f8\u5bf9\u8f83\u957f\uff0c\u4e0d\u5982count()\u548cCounter\u65b9\u6cd5\u7b80\u6d01\u3002<\/p>\n<\/p>\n
\u56db\u3001\u4f7f\u7528\u5217\u8868\u63a8\u5bfc\u5f0f<\/h3>\n<\/p>\n
\u5217\u8868\u63a8\u5bfc\u5f0f\u662f\u4e00\u79cd\u7b80\u6d01\u7684Python\u8bed\u6cd5\uff0c\u53ef\u4ee5\u7528\u6765\u751f\u6210\u5217\u8868\u3002\u901a\u8fc7\u5217\u8868\u63a8\u5bfc\u5f0f\uff0c\u6211\u4eec\u53ef\u4ee5\u751f\u6210\u4e00\u4e2a\u5305\u542b\u6240\u6709\u76ee\u6807\u5143\u7d20\u7684\u5217\u8868\uff0c\u7136\u540e\u7edf\u8ba1\u5176\u957f\u5ea6\u3002<\/p>\n<\/p>\n
# \u793a\u4f8b\u4ee3\u7801<\/p>\n
my_list = [1, 2, 3, 2, 2, 4, 2, 5]<\/p>\n
element = 2<\/p>\n
count = len([item for item in my_list if item == element])<\/p>\n
print(f"\u5143\u7d20{element}\u5728\u5217\u8868\u4e2d\u51fa\u73b0\u4e86{count}\u6b21")<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4f18\u70b9<\/strong>\uff1a\u4ee3\u7801\u7b80\u6d01\u3001\u4f18\u96c5\u3002<\/p>\n<\/p>\n
\u7f3a\u70b9<\/strong>\uff1a\u5bf9\u4e8e\u975e\u5e38\u5927\u7684\u5217\u8868\uff0c\u6548\u7387\u53ef\u80fd\u4e0d\u5982\u5176\u4ed6\u65b9\u6cd5\u3002<\/p>\n<\/p>\n
\u4e94\u3001\u4f7f\u7528Numpy\u5e93<\/h3>\n<\/p>\n
\u5982\u679c\u5217\u8868\u4e2d\u5305\u542b\u5927\u91cf\u6570\u636e\uff0c\u5e76\u4e14\u4f60\u9700\u8981\u8fdb\u884c\u9ad8\u6548\u7684\u6570\u503c\u8ba1\u7b97\uff0c\u53ef\u4ee5\u8003\u8651\u4f7f\u7528Numpy\u5e93\u3002Numpy\u5e93\u63d0\u4f9b\u4e86\u9ad8\u6548\u7684\u6570\u7ec4\u64cd\u4f5c\u65b9\u6cd5\uff0c\u53ef\u4ee5\u5feb\u901f\u7edf\u8ba1\u5143\u7d20\u51fa\u73b0\u7684\u6b21\u6570\u3002<\/p>\n<\/p>\n
import numpy as np<\/p>\n
\u793a\u4f8b\u4ee3\u7801<\/strong><\/h2>\n
my_list = [1, 2, 3, 2, 2, 4, 2, 5]<\/p>\n
element = 2<\/p>\n
np_array = np.array(my_list)<\/p>\n
count = np.sum(np_array == element)<\/p>\n
print(f"\u5143\u7d20{element}\u5728\u5217\u8868\u4e2d\u51fa\u73b0\u4e86{count}\u6b21")<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4f18\u70b9<\/strong>\uff1a\u9ad8\u6548\uff0c\u9002\u5408\u5927\u6570\u636e\u91cf\u7684\u8ba1\u7b97\u3002<\/p>\n<\/p>\n
\u7f3a\u70b9<\/strong>\uff1a\u9700\u8981\u5b89\u88c5\u548c\u5b66\u4e60Numpy\u5e93\uff0c\u9002\u5408\u6709\u4e00\u5b9a\u7f16\u7a0b\u57fa\u7840\u7684\u7528\u6237\u3002<\/p>\n<\/p>\n
\u516d\u3001\u4f7f\u7528Pandas\u5e93<\/h3>\n<\/p>\n
Pandas\u5e93\u4e5f\u662f\u6570\u636e\u5904\u7406\u548c\u5206\u6790\u7684\u5e38\u7528\u5de5\u5177\u3002\u901a\u8fc7\u5c06\u5217\u8868\u8f6c\u6362\u4e3aPandas\u7684Series\u5bf9\u8c61\uff0c\u53ef\u4ee5\u65b9\u4fbf\u5730\u7edf\u8ba1\u5143\u7d20\u51fa\u73b0\u7684\u6b21\u6570\u3002<\/p>\n<\/p>\n
import pandas as pd<\/p>\n
\u793a\u4f8b\u4ee3\u7801<\/strong><\/h2>\n
my_list = [1, 2, 3, 2, 2, 4, 2, 5]<\/p>\n
element = 2<\/p>\n
series = pd.Series(my_list)<\/p>\n
count = series.value_counts()[element]<\/p>\n
print(f"\u5143\u7d20{element}\u5728\u5217\u8868\u4e2d\u51fa\u73b0\u4e86{count}\u6b21")<\/p>\n
<\/code><\/pre>\n<\/p>\n
\u4f18\u70b9<\/strong>\uff1aPandas\u5e93\u529f\u80fd\u5f3a\u5927\uff0c\u9002\u5408\u590d\u6742\u7684\u6570\u636e\u5206\u6790\u4efb\u52a1\u3002<\/p>\n<\/p>\n
\u7f3a\u70b9<\/strong>\uff1a\u9700\u8981\u5b89\u88c5\u548c\u5b66\u4e60Pandas\u5e93\uff0c\u9002\u5408\u6570\u636e\u5206\u6790\u9700\u6c42\u8f83\u9ad8\u7684\u7528\u6237\u3002<\/p>\n<\/p>\n
\u4e03\u3001\u603b\u7ed3<\/h3>\n<\/p>\n
\u901a\u8fc7\u4e0a\u8ff0\u51e0\u79cd\u65b9\u6cd5\uff0c\u6211\u4eec\u53ef\u4ee5\u770b\u5230\u5728Python\u4e2d\u7edf\u8ba1\u5217\u8868\u4e2d\u67d0\u4e00\u9879\u7684\u4e2a\u6570\u6709\u591a\u79cd\u9014\u5f84\u3002count()\u65b9\u6cd5\u7b80\u5355\u76f4\u89c2\u3001collections.Counter\u7c7b\u529f\u80fd\u5f3a\u5927\u3001\u5faa\u73af\u548c\u6761\u4ef6\u5224\u65ad\u7075\u6d3b\u3001\u5217\u8868\u63a8\u5bfc\u5f0f\u7b80\u6d01\u3001Numpy\u548cPandas\u5e93\u9ad8\u6548\u9002\u5408\u5927\u6570\u636e\u91cf\u8ba1\u7b97<\/strong>\u3002\u9009\u62e9\u54ea\u79cd\u65b9\u6cd5\u53d6\u51b3\u4e8e\u5177\u4f53\u7684\u9700\u6c42\u548c\u6570\u636e\u89c4\u6a21\u3002<\/p>\n<\/p>\n
\u65e0\u8bba\u662f\u521d\u5b66\u8005\u8fd8\u662f\u6709\u7ecf\u9a8c\u7684\u7a0b\u5e8f\u5458\uff0c\u638c\u63e1\u8fd9\u4e9b\u7edf\u8ba1\u65b9\u6cd5\u90fd\u80fd\u5927\u5927\u63d0\u9ad8\u7f16\u7a0b\u6548\u7387\u548c\u6570\u636e\u5904\u7406\u80fd\u529b\u3002\u5e0c\u671b\u672c\u6587\u80fd\u4e3a\u4f60\u63d0\u4f9b\u6709\u4ef7\u503c\u7684\u53c2\u8003\uff0c\u5e2e\u52a9\u4f60\u5728\u5b9e\u9645\u9879\u76ee\u4e2d\u66f4\u597d\u5730\u89e3\u51b3\u7edf\u8ba1\u95ee\u9898\u3002<\/p>\n<\/p>\n
\u76f8\u5173\u95ee\u7b54FAQs\uff1a<\/strong><\/h2>\n
 \u5982\u4f55\u5728Python\u4e2d\u5feb\u901f\u7edf\u8ba1\u5217\u8868\u4e2d\u67d0\u4e00\u9879\u7684\u6570\u91cf\uff1f<\/strong>
\u5728Python\u4e2d\uff0c\u53ef\u4ee5\u4f7f\u7528count()<\/code>\u65b9\u6cd5\u6765\u7edf\u8ba1\u5217\u8868\u4e2d\u67d0\u4e00\u9879\u7684\u4e2a\u6570\u3002\u53ea\u9700\u8c03\u7528\u8be5\u65b9\u6cd5\u5e76\u4f20\u5165\u4f60\u60f3\u8981\u7edf\u8ba1\u7684\u5143\u7d20\uff0c\u4ee3\u7801\u793a\u4f8b\u5982\u4e0b\uff1a<\/p>\n
my_list = [1, 2, 3, 2, 1, 4]\ncount_of_twos = my_list.count(2)\nprint(count_of_twos)  # \u8f93\u51fa\uff1a2\n<\/code><\/pre>\n
\u8fd9\u79cd\u65b9\u6cd5\u7b80\u5355\u76f4\u63a5\uff0c\u9002\u7528\u4e8e\u4efb\u4f55\u7c7b\u578b\u7684\u5217\u8868\u5143\u7d20\u3002<\/p>\n
\u5728Python\u4e2d\u662f\u5426\u6709\u5176\u4ed6\u65b9\u6cd5\u53ef\u4ee5\u7edf\u8ba1\u5217\u8868\u4e2d\u67d0\u4e00\u9879\u7684\u4e2a\u6570\uff1f<\/strong>
\u9664\u4e86\u4f7f\u7528count()<\/code>\u65b9\u6cd5\uff0c\u8fd8\u53ef\u4ee5\u501f\u52a9collections<\/code>\u6a21\u5757\u4e2d\u7684Counter<\/code>\u7c7b\u6765\u5b9e\u73b0\u66f4\u590d\u6742\u7684\u7edf\u8ba1\u9700\u6c42\u3002\u4f7f\u7528Counter<\/code>\u65f6\uff0c\u53ef\u4ee5\u83b7\u5f97\u5217\u8868\u4e2d\u6240\u6709\u5143\u7d20\u7684\u9891\u7387\u5206\u5e03\uff0c\u4f8b\u5982\uff1a<\/p>\n
from collections import Counter\n\nmy_list = [1, 2, 3, 2, 1, 4]\ncounter = Counter(my_list)\nprint(counter[2])  # \u8f93\u51fa\uff1a2\n<\/code><\/pre>\n
\u8fd9\u79cd\u65b9\u6cd5\u7279\u522b\u9002\u5408\u4e8e\u9700\u8981\u540c\u65f6\u7edf\u8ba1\u591a\u4e2a\u5143\u7d20\u6570\u91cf\u7684\u60c5\u51b5\u3002<\/p>\n
\u7edf\u8ba1\u5217\u8868\u4e2d\u67d0\u4e00\u9879\u4e2a\u6570\u7684\u6027\u80fd\u5982\u4f55\uff1f<\/strong>
\u4f7f\u7528count()<\/code>\u65b9\u6cd5\u7684\u65f6\u95f4\u590d\u6742\u5ea6\u4e3aO(n)\uff0c\u8fd9\u610f\u5473\u7740\u5728\u5217\u8868\u8f83\u5927\u65f6\uff0c\u6027\u80fd\u53ef\u80fd\u4f1a\u53d7\u5230\u5f71\u54cd\u3002\u5982\u679c\u4f60\u53ea\u9700\u8981\u7edf\u8ba1\u4e00\u6b21\u67d0\u4e00\u9879\u7684\u6570\u91cf\uff0ccount()<\/code>\u65b9\u6cd5\u662f\u5408\u9002\u7684\u9009\u62e9\uff1b\u4f46\u5982\u679c\u9700\u8981\u591a\u6b21\u7edf\u8ba1\u6216\u7edf\u8ba1\u591a\u4e2a\u5143\u7d20\uff0c\u5efa\u8bae\u4f7f\u7528Counter<\/code>\u7c7b\uff0c\u56e0\u4e3a\u5b83\u53ea\u9700\u904d\u5386\u4e00\u6b21\u5217\u8868\uff0c\u6027\u80fd\u66f4\u4f18\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"\u4f7f\u7528Python\u7edf\u8ba1\u5217\u8868\u4e2d\u67d0\u4e00\u9879\u4e2a\u6570\uff0c\u53ef\u4ee5\u91c7\u7528\u591a\u79cd\u65b9\u6cd5\uff0c\u5982count()\u65b9\u6cd5\u3001collections\u6a21\u5757\u4e2d\u7684C […]","protected":false},"author":3,"featured_media":1138561,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[37],"tags":[],"acf":[],"_links":{"self":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/1138552"}],"collection":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/comments?post=1138552"}],"version-history":[{"count":"1","href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/1138552\/revisions"}],"predecessor-version":[{"id":1138562,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/posts\/1138552\/revisions\/1138562"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media\/1138561"}],"wp:attachment":[{"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/media?parent=1138552"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/categories?post=1138552"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/docs.pingcode.com\/wp-json\/wp\/v2\/tags?post=1138552"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}