{"id":3057,"date":"2022-02-27T10:40:17","date_gmt":"2022-02-27T02:40:17","guid":{"rendered":"https:\/\/egonlin.com\/?p=3057"},"modified":"2022-02-27T11:01:17","modified_gmt":"2022-02-27T03:01:17","slug":"%e5%86%b3%e7%ad%96%e6%a0%91c4-5%e7%ae%97%e6%b3%95","status":"publish","type":"post","link":"https:\/\/egonlin.com\/?p=3057","title":{"rendered":"\u7b2c\u4e8c\u8282\uff1a\u51b3\u7b56\u6811C4.5\u7b97\u6cd5"},"content":{"rendered":"

\u51b3\u7b56\u6811C4.5\u7b97\u6cd5<\/h1>\n

  \u4e3a\u4e86\u89e3\u51b3\u51b3\u7b56\u6811ID3\u7b97\u6cd5\u7684\u4e0d\u8db3\uff0cID3\u7b97\u6cd5\u7684\u4f5c\u8005\u6606\u5170\u57fa\u4e8e\u5b83\u7684\u4e0d\u8db3\u6539\u8fdb\u4e86\u51b3\u7b56\u6811ID3\u7b97\u6cd5\u3002\u4f46\u662f\u53ef\u80fd\u4f1a\u6709\u4eba\u6709\u7591\u95ee\uff0c\u65e2\u7136\u4e0a\u4e00\u4e2a\u51b3\u7b56\u6811\u7b97\u6cd5\u53eb\u505aID3\u7b97\u6cd5\uff0c\u4e3a\u4ec0\u4e48\u6539\u8fdb\u7248\u672c\u4e0d\u53eb\u505aID4\u6216\u8005ID5\u5462\uff1f\u56e0\u4e3a\u5f53\u65f6\u51b3\u7b56\u6811\u8fc7\u4e8e\u706b\u7206\uff0c\u6709\u4eba\u4e8c\u6b21\u521b\u65b0\u628aID4\u3001ID5\u90fd\u7528\u6389\u4e86\uff0c\u7531\u6b64\u4f5c\u8005\u53e6\u8f9f\u8e4a\u5f84\u628aID3\u7b97\u6cd5\u7684\u6539\u8fdb\u7248\u672c\u79f0\u4e3aC4\u7b97\u6cd5\uff0c\u540e\u6765C4\u7b97\u6cd5\u53c8\u4e00\u6b21\u5347\u7ea7\u4fbf\u6709\u4e86\u73b0\u5728\u7684C4.5\u7b97\u6cd5\u3002<\/p>\n

\u51b3\u7b56\u6811C4.5\u7b97\u6cd5\u5b66\u4e60\u76ee\u6807<\/h1>\n
    \n
  1. \u4f7f\u7528C4.5\u7b97\u6cd5\u5bf9\u8fde\u7eed\u7279\u5f81\u503c\u79bb\u6563\u5316<\/li>\n
  2. \u4fe1\u606f\u589e\u76ca\u6bd4<\/li>\n
  3. \u4f7f\u7528C4.5\u7b97\u6cd5\u5bf9\u7279\u5f81\u503c\u52a0\u6743<\/li>\n
  4. \u51b3\u7b56\u6811C4.5\u7b97\u6cd5\u6b65\u9aa4<\/li>\n
  5. \u51b3\u7b56\u6811C4.5\u7b97\u6cd5\u4f18\u7f3a\u70b9<\/li>\n<\/ol>\n

    \u51b3\u7b56\u6811C4.5\u7b97\u6cd5\u8be6\u89e3<\/h1>\n

      \u4e0a\u4e00\u6b21\u8bf4\u5230\u51b3\u7b56\u6811ID3\u7b97\u6cd5\u67094\u4e2a\u7f3a\u70b9\uff0c\u800c\u8fd9\u6b21\u4f5c\u8005\u4e5f\u662f\u57fa\u4e8e\u8fd94\u4e2a\u7f3a\u70b9\u6539\u8fdb\u4e86\u7b97\u6cd5\uff0c\u4e5f\u5c31\u662f\u73b0\u5728\u7684C4.5\u7b97\u6cd5\u3002<\/p>\n

      \u5047\u8bbe\u73b0\u6709\u4e00\u4e2a\u8bad\u7ec3\u96c6$D$\uff0c\u7279\u5f81\u96c6$A$\uff0c\u8bad\u7ec3\u96c6\u4e2d\u6709$m$\u4e2a\u6837\u672c\uff0c\u6bcf\u4e2a\u6837\u672c\u6709$n$\u4e2a\u7279\u5f81\uff0c\u6211\u4eec\u901a\u8fc7\u8be5\u8bad\u7ec3\u96c6\u804a\u4e00\u804a\u4f5c\u8005\u5bf9C4.5\u7b97\u6cd5\u505a\u4e86\u54ea\u4e9b\u6539\u8fdb\u3002<\/p>\n

    \u8fde\u7eed\u7279\u5f81\u503c\u79bb\u6563\u5316<\/h2>\n

      ID3\u7b97\u6cd5\u7684\u7b2c\u4e00\u4e2a\u7f3a\u70b9\uff1a\u6ca1\u6709\u8003\u8651\u5230\u8fde\u7eed\u503c\u7684\u60c5\u51b5\u3002<\/p>\n

      \u5047\u8bbe\u73b0\u6709\u4e00\u4e2a\u7279\u5f81$F$\u7684\u7279\u5f81\u503c\u4e3a\u8fde\u7eed\u503c\uff0c\u4ece\u5927\u5230\u5c0f\u6392\u5e8f\u4e3a$f_1,f_2,\\ldots,f_m$\uff0cC4.5\u7b97\u6cd5\u5bf9\u76f8\u90bb\u6837\u672c\u95f4\u7684\u7279\u5f81\u503c$fi,f<\/em>{i+1}$\u53d6\u5e73\u5747\u6570\uff0c\u4e00\u5171\u53ef\u4ee5\u5f97\u5230$m-1$\u4e2a\u5212\u5206\u70b9\uff0c\u5176\u4e2d\u7b2c$j$\u4e2a\u5212\u5206\u70b9\u53ef\u4ee5\u8868\u793a\u4e3a
    \n$$
    \nS_j = {\\frac {fi + f<\/em>{i+1}} {2}}
    \n$$
    \n\u5bf9\u4e8e\u8fd9$m-1$\u4e2a\u5212\u5206\u70b9\uff0c\u5206\u522b\u8ba1\u7b97\u4ee5\u8be5\u70b9\u4f5c\u4e3a\u4e8c\u5143\u5206\u7c7b\u70b9\u7684\u4fe1\u606f\u589e\u76ca\u6bd4<\/strong>\uff0c\u9009\u62e9\u4fe1\u606f\u589e\u76ca\u6bd4\u6700\u5927\u7684\u70b9<\/strong>\u4f5c\u4e3a\u8be5\u8fde\u7eed\u7279\u5f81\u7684\u4e8c\u5143\u79bb\u6563\u5206\u7c7b\u70b9\uff0c\u628a\u6539\u70b9\u8bb0\u4f5c$f_t$\uff0c\u5219\u7279\u5f81\u503c\u5c0f\u4e8e$f_t$\u7684\u70b9\u8bb0\u4f5c$c_1$\uff1b\u7279\u5f81\u503c\u5927\u4e8e$f_t$\u7684\u70b9\u8bb0\u4f5c$c_2$\uff0c\u8fd9\u6837\u5c31\u5b9e\u73b0\u4e86\u8fde\u7eed\u7279\u5f81\u503c\u7684\u79bb\u6563\u5316\u3002<\/p>\n

    \u4fe1\u606f\u589e\u76ca\u6bd4<\/h2>\n

      ID3\u7b97\u6cd5\u7684\u7b2c\u4e8c\u4e2a\u7f3a\u70b9\uff1a\u4ee5\u4fe1\u606f\u589e\u76ca\u4f5c\u4e3a\u5212\u5206\u8bad\u7ec3\u6570\u636e\u96c6\u7684\u7279\u5f81\uff0c\u5b58\u5728\u4e8e\u504f\u5411\u4e8e\u9009\u62e9\u53d6\u503c\u8f83\u591a\u7684\u7279\u5f81\u7684\u95ee\u9898\u3002<\/p>\n

      \u4fe1\u606f\u589e\u76ca\u4f5c\u4e3a\u6807\u51c6\u5bb9\u6613\u504f\u5411\u4e8e\u53d6\u503c\u8f83\u591a\u7684\u7279\u5f81\uff0c\u56e0\u6b64\u53ef\u4ee5\u4f7f\u7528\u4fe1\u606f\u589e\u76ca\u6bd4\u4f5c\u4e3a\u5212\u5206\u8282\u70b9\u7684\u6807\u51c6\u3002\u4fe1\u606f\u589e\u76ca\u6bd4\u7684\u6982\u5ff5\u5df2\u7ecf\u5728\u300a\u71b5\u548c\u4fe1\u606f\u589e\u76ca\u300b\u4e00\u6587\u4e2d\u4ecb\u7ecd\u8fc7\uff0c\u8fd9\u91cc\u53ea\u7ed9\u51fa\u516c\u5f0f
    \n$$
    \ng_R(D,A) = {\\frac{g(D,A)}{H_A(D)}}
    \n$$
    \n  \u7531\u4e8e\u7279\u5f81\u8d8a\u591a\u7684\u7279\u5f81\u5bf9\u5e94\u7684\u7279\u5f81\u71b5$H_A(D)$\u8d8a\u5927\uff0c\u5219\u4fe1\u606f\u589e\u76ca\u6bd4$g_R(D,A)$\u5219\u4f1a\u53d8\u5c0f\uff0c\u56e0\u6b64\u53ef\u4ee5\u6821\u6b63\u4fe1\u606f\u589e\u76ca\u5bb9\u6613\u504f\u5411\u4e8e\u53d6\u503c\u8f83\u591a\u7684\u7279\u5f81\u7684\u95ee\u9898\u3002<\/p>\n

    \u526a\u679d<\/h2>\n

      ID3\u7b97\u6cd5\u7684\u7b2c\u4e09\u4e2a\u7f3a\u70b9\uff1a\u6ca1\u6709\u8003\u8651\u8fc7\u62df\u5408\u95ee\u9898\u3002<\/p>\n

      \u51b3\u7b56\u6811\u4e00\u822c\u91c7\u7528\u526a\u679d\u7684\u65b9\u6cd5\u89e3\u51b3\u8fc7\u62df\u5408\u95ee\u9898\uff0c\u526a\u679d\u7684\u5177\u4f53\u601d\u8def\u5c06\u5728CART\u6811\u4e00\u6587\u4e2d\u7ec6\u8bb2\u3002<\/p>\n

    \u7279\u5f81\u503c\u52a0\u6743<\/h2>\n

      ID3\u7b97\u6cd5\u7684\u7b2c\u56db\u4e2a\u7f3a\u70b9\uff1a\u6ca1\u6709\u8003\u8651\u7279\u5f81\u4e2d\u542b\u6709\u7f3a\u5931\u503c\u7684\u60c5\u51b5\u3002<\/p>\n

      \u5047\u8bbe\u67d0\u4e2a\u7279\u5f81$F$\u67092\u4e2a\u7279\u5f81\u503c$f_1,f_2$\uff0c\u5148\u8bbe\u5b9a\u7f3a\u5931$F$\u7279\u5f81\u7684\u6837\u672c$D_i$\u7684\u5173\u4e8e\u7279\u5f81$F$\u7684\u7279\u5f81\u503c\u6743\u91cd\u90fd\u4e3a1\uff0c\u5373$f_1$\u548c$f_2$\u3002\u5047\u8bbe$2$\u4e2a\u7279\u5f81\u503c\u5bf9\u5e94\u7684\u65e0\u7f3a\u5931\u503c\u7684\u6837\u672c\u4e2a\u6570\u4e3a$3$\u548c$5$\uff0c\u73b0\u5728\u628a\u7279\u5f81\u503c$f_1,f_2$\u91cd\u65b0\u5212\u5165\u6837\u672c$D_i$\u4e2d\uff0c\u5728\u6837\u672c$D_i$\u4e2d$f_1$\u7684\u6743\u91cd\u8c03\u8282\u4e3a${\\frac{3}{8}}$\uff0c$f_2$\u7684\u6743\u91cd\u8c03\u8282\u4e3a${\\frac{5}{8}}$\uff0c\u5373\u6837\u672c$D_i$\u7684\u7279\u5f81$F$\u7684\u7279\u5f81\u503c\u4e3a${\\frac{3}{8}}f_1\u548c{\\frac{5}{8}}<\/em>f_2$\u3002<\/p>\n

      \u8ba1\u7b97\u6837\u672c$D_i$\u7684\u7279\u5f81$F$\u7684\u4fe1\u606f\u589e\u76ca\u6bd4\u7684\u65f6\u5019\uff0c\u53ca\u8ba1\u7b97${\\frac{3}{8}}f_1$\u548c${\\frac{5}{8}}<\/em>f_2$\u7684\u4fe1\u606f\u589e\u76ca\u6bd4\u3002<\/p>\n

    \u51b3\u7b56\u6811C4.5\u7b97\u6cd5\u6d41\u7a0b<\/h1>\n

    \u8f93\u5165<\/h2>\n

      \u5047\u8bbe\u73b0\u6709\u4e00\u4e2a\u8bad\u7ec3\u96c6$D$\uff0c\u7279\u5f81\u96c6$A$\uff0c\u9608\u503c$\\epsilon$\u3002<\/p>\n

    \u8f93\u51fa<\/h2>\n

      C4.5\u7b97\u6cd5\u51b3\u7b56\u6811\u3002<\/p>\n

    \u6d41\u7a0b<\/h2>\n
      \n
    1. \u521d\u59cb\u5316\u4fe1\u606f\u589e\u76ca\u7684\u9608\u503c$\\epsilon$<\/li>\n
    2. \u5982\u679c$D$\u4e2d\u7684\u6240\u6709\u6837\u672c\u90fd\u5c5e\u4e8e\u540c\u4e00\u7c7b$C_k$\uff0c\u5219\u8fd4\u56de\u5355\u8282\u70b9\u6811$T$\uff0c\u6807\u8bb0\u7c7b\u522b\u4e3a$C_k$<\/li>\n
    3. \u5982\u679c$A$\u4e3a\u7a7a\u96c6\uff0c\u5219\u8fd4\u56de\u5355\u8282\u70b9\u6811$T$\uff0c\u6807\u8bb0\u7c7b\u522b\u4e3a$D$\u4e2d\u6837\u672c\u6570\u6700\u5927\u7684\u7c7b$C_k$<\/li>\n
    4. \u8ba1\u7b97$A$\u4e2d\u5404\u4e2a\u7279\u5f81\u5bf9\u8f93\u51fa$D$\u7684\u4fe1\u606f\u589e\u76ca\u6bd4<\/strong>\uff0c\u9009\u62e9\u4fe1\u606f\u589e\u76ca\u6bd4<\/strong>\u6700\u5927\u7684$A_g$<\/li>\n
    5. \u5982\u679c$A_g$\u5c0f\u4e8e\u9608\u503c$\\epsilon$\uff0c\u5219\u8fd4\u56de\u5355\u8282\u70b9\u6570$T$\uff0c\u6807\u8bb0\u7c7b\u522b\u4e3a$D$\u4e2d\u6837\u672c\u6570\u6700\u5927\u7684\u7c7b$C_k$<\/li>\n
    6. \u5982\u679c$A_g$\u5927\u4e8e\u9608\u503c$\\epsilon$\uff0c\u5219\u6309\u7167\u7279\u5f81$Ag$\u7684\u4e0d\u540c\u53d6\u503c$A<\/em>{g_i}$\u628a$D$\u5206\u5272\u6210\u82e5\u5e72\u4e2a\u5b50\u96c6$Di$\uff0c\u6bcf\u4e2a\u5b50\u96c6\u751f\u6210\u4e00\u4e2a\u5b50\u8282\u70b9\uff0c\u5b50\u8282\u70b9\u5bf9\u5e94\u7279\u5f81\u503c\u4e3a$A<\/em>{g_i}$\uff0c\u9012\u5f52\u8c03\u7528$2-6$\u6b65\uff0c\u5f97\u5230\u5b50\u6811$T_i$\u5e76\u8fd4\u56de<\/li>\n<\/ol>\n

      \u51b3\u7b56\u6811C4.5\u7b97\u6cd5\u7684\u4f18\u7f3a\u70b9<\/h1>\n

      \u4f18\u70b9<\/h2>\n
        \n
      1. \u7406\u8bba\u6e05\u6670\uff0c\u65b9\u6cd5\u7b80\u5355<\/li>\n
      2. \u5b66\u4e60\u80fd\u529b\u5f3a<\/li>\n<\/ol>\n

        \u7f3a\u70b9<\/h2>\n
          \n
        1. \u53ea\u80fd\u7528\u4e8e\u5206\u7c7b<\/li>\n
        2. C4.5\u7b97\u6cd5\u7531\u4e8e\u4f7f\u7528\u4e86\u71b5\u7684\u6982\u5ff5\uff0c\u5373\u51b3\u7b56\u6811\u7684\u751f\u6210\u9700\u8981\u5927\u91cf\u7684\u71b5\u503c\u8ba1\u7b97\uff0c\u5e76\u4e14\u5982\u679c\u7279\u5f81\u503c\u4e3a\u8fde\u7eed\u503c\uff0c\u8fd8\u9700\u8981\u8fdb\u884c\u6392\u5e8f\u8fd0\u7b97<\/li>\n
        3. \u4f7f\u7528\u6a21\u578b\u8f83\u4e3a\u590d\u6742\u7684\u591a\u53c9\u6811\u7ed3\u6784<\/li>\n<\/ol>\n

          \u5c0f\u7ed3<\/h1>\n

            \u51b3\u7b56\u6811C4.5\u7b97\u6cd5\u6d41\u7a0b\u4e0a\u548c\u51b3\u7b56\u6811ID3\u7b97\u6cd5\u5927\u76f8\u5f84\u5ead\uff0c\u53ea\u662f\u5728\u51b3\u7b56\u6811ID3\u7b97\u6cd5\u4e0a\u7684\u67d0\u4e00\u6b65\u6d41\u7a0b\u8fdb\u884c\u4e86\u4f18\u5316\uff0c\u603b\u800c\u8a00\u4e4b\uff0c\u5b83\u8fd9\u79cd\u5904\u7406\u65b9\u5f0f\u8fd8\u662f\u6cbb\u6807\u4e0d\u6cbb\u672c\u7684\uff0c\u5e76\u4e14\u8fd8\u662f\u65e0\u6cd5\u5904\u7406\u56de\u5f52\u95ee\u9898\u3002<\/p>\n

            \u63a5\u4e0b\u6765\u6211\u4eec\u5c06\u8981\u5c06\u4e00\u4e2a\u6539\u9769\u610f\u4e49\u7684\u51b3\u7b56\u6811\uff0c\u76ee\u524dscikit-learn\u7b97\u6cd5\u4e2d\u4ee5\u53ca\u96c6\u6210\u5b66\u4e60\u4e2d\u90fd\u4f7f\u7528\u8be5\u6811\u4f5c\u4e3a\u76ee\u6807\u51b3\u7b56\u6811\uff0c\u5373\u51b3\u7b56\u6811CART\u7b97\u6cd5\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"

          \u51b3\u7b56\u6811C4.5\u7b97\u6cd5   \u4e3a\u4e86\u89e3\u51b3\u51b3\u7b56\u6811ID3\u7b97\u6cd5\u7684\u4e0d\u8db3\uff0cID3\u7b97\u6cd5\u7684\u4f5c\u8005\u6606\u5170\u57fa\u4e8e\u5b83\u7684\u4e0d\u8db3\u6539 […]<\/p>\n","protected":false},"author":3,"featured_media":3066,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[276,289],"tags":[],"_links":{"self":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts\/3057"}],"collection":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3057"}],"version-history":[{"count":0,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts\/3057\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/media\/3066"}],"wp:attachment":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3057"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3057"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3057"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}