{"id":3055,"date":"2022-02-27T10:38:14","date_gmt":"2022-02-27T02:38:14","guid":{"rendered":"https:\/\/egonlin.com\/?p=3055"},"modified":"2022-02-27T11:01:32","modified_gmt":"2022-02-27T03:01:32","slug":"%e5%86%b3%e7%ad%96%e6%a0%91id3%e7%ae%97%e6%b3%95","status":"publish","type":"post","link":"https:\/\/egonlin.com\/?p=3055","title":{"rendered":"\u7b2c\u4e00\u8282\uff1a\u51b3\u7b56\u6811ID3\u7b97\u6cd5"},"content":{"rendered":"

\u51b3\u7b56\u6811ID3\u7b97\u6cd5<\/h1>\n

  \u51b3\u7b56\u6811\uff08decision tree\uff09\u662f\u4e00\u79cd\u57fa\u672c\u7684\u5206\u7c7b\u4e0e\u56de\u5f52\u65b9\u6cd5\uff0c\u540c\u65f6\u7531\u4e8e\u81ea\u8eab\u662f\u5f31\u5206\u7c7b\u5668\u7279\u522b\u9002\u5408\u96c6\u6210\u5b66\u4e60\uff0c\u4f8b\u5982\u968f\u673a\u68ee\u6797\u3001XgBoost\u3002<\/p>\n

  \u672c\u6587\u5c06\u901a\u8fc7ID3\u7b97\u6cd5\u5e26\u5927\u5bb6\u5165\u95e8\u51b3\u7b56\u6811\uff0c\u4e4b\u540e\u4f1a\u53e6\u5199\u6587\u7ae0\u8c08\u8c08C4.5\u7b97\u6cd5\u548cCART\u5206\u7c7b\u56de\u5f52\u6811\u3002<\/p>\n

\u51b3\u7b56\u6811ID3\u7b97\u6cd5\u5b66\u4e60\u76ee\u6807<\/h1>\n
    \n
  1. \u4fe1\u606f\u589e\u76ca<\/li>\n
  2. \u51b3\u7b56\u6811ID3\u7b97\u6cd5\u6d41\u7a0b<\/li>\n
  3. \u51b3\u7b56\u6811ID3\u7b97\u6cd5\u4f18\u7f3a\u70b9<\/li>\n<\/ol>\n

    \u51b3\u7b56\u6811\u5f15\u5165<\/h1>\n

      \u5047\u8bbe\u94f6\u884c\u9700\u8981\u6784\u9020\u4e00\u4e2a\u5f81\u4fe1\u7cfb\u7edf\u7528\u6765\u53d1\u653e\u8d37\u6b3e\uff0c\u5982\u679c\u4f60\u662f\u6784\u5efa\u8be5\u7cfb\u7edf\u7684\u4eba\uff0c\u4f60\u4f1a\u5982\u4f55\u6784\u5efa\u8be5\u7cfb\u7edf\u5462\uff1f<\/p>\n

      \u6211\u8bf4\u8bf4\u6211\u5c06\u5982\u4f55\u6784\u5efa\u4e00\u4e2a\u94f6\u884c\u7684\u5f81\u4fe1\u7cfb\u7edf\uff0c\u9996\u5148\uff0c\u6211\u4f1a\u5224\u65ad\u5f81\u4fe1\u4eba\u7684\u5e74\u6536\u5165\u6709\u6ca1\u670950\u4e07\uff0c\u5982\u679c\u6709\u6211\u76f4\u63a5\u5224\u5b9a\u4ed6\u53ef\u4ee5\u8d37\u6b3e\uff0c\u5982\u679c\u6ca1\u6709\u6211\u4f1a\u518d\u505a\u5176\u4ed6\u7684\u5224\u65ad\uff1b\u5176\u6b21\uff0c\u5224\u65ad\u5f81\u4fe1\u4eba\u6709\u6ca1\u6709\u623f\u4ea7\uff0c\u5982\u679c\u6709\u623f\u4ea7\u4e5f\u5c31\u662f\u8bf4\u4ed6\u6709\u4e86\u53ef\u4ee5\u62b5\u62bc\u7684\u4e0d\u52a8\u4ea7\uff0c\u65e2\u53ef\u4ee5\u5224\u5b9a\u4ed6\u53ef\u4ee5\u8d37\u6b3e\uff0c\u5982\u679c\u6ca1\u6709\uff0c\u5219\u4e0d\u80fd\u8d37\u6b3e\u2026\u2026<\/p>\n

      \u4e0a\u8ff0\u6574\u4e2a\u8fc7\u7a0b\u5176\u5b9e\u5c31\u662f\u51b3\u7b56\u6811\u5b9e\u73b0\u7684\u4e00\u4e2a\u8fc7\u7a0b\uff0c\u63a5\u4e0b\u6765\u5c06\u4ece\u7406\u8bba\u5c42\u9762\u62bd\u8c61\u7684\u8bb2\u89e3\u4e09\u79cd\u5f62\u5f0f\u7684\u51b3\u7b56\u6811\u3002<\/p>\n

    [\u5916\u94fe\u56fe\u7247\u8f6c\u5b58\u5931\u8d25,\u6e90\u7ad9\u53ef\u80fd\u6709\u9632\u76d7\u94fe\u673a\u5236,\u5efa\u8bae\u5c06\u56fe\u7247\u4fdd\u5b58\u4e0b\u6765\u76f4\u63a5\u4e0a\u4f20(img-5KPug9Zs-1582805130189)(img\/\u51b3\u7b56\u6811ID3\u7b97\u6cd5-\u51b3\u7b56\u6811\u5224\u65ad\u4e2a\u4eba\u4fe1\u7528\u8d37\u6b3e.png)]<\/p>\n

    \u51b3\u7b56\u6811ID3\u7b97\u6cd5\u8be6\u89e3<\/h1>\n

    if\u2026else\u548c\u51b3\u7b56\u6811<\/h2>\n

      \u5982\u4e0a\u4e00\u8282\u7684\u5f81\u4fe1\u7cfb\u7edf\u6784\u5efa\u4e00\u6837\uff0c\u51b3\u7b56\u6811ID3\u7b97\u6cd5\u7684\u601d\u60f3\u5176\u5b9e\u5f88\u7b80\u5355\uff0c\u5f53\u4f60\u5728\u4f7f\u7528$if\\ldots{elif}\\ldots{else}$\u6572\u4ee3\u7801\u7684\u65f6\u5019\u5176\u5b9e\u5c31\u662f\u5728\u4f7f\u7528\u51b3\u7b56\u6811\u7684\u601d\u60f3\uff0c\u4f46\u662f\u4f60\u6709\u6ca1\u6709\u60f3\u8fc7\u628a\u54ea\u4e2a\u5224\u65ad\u6761\u4ef6\u653e\u5728$if$\u4e0a\u56de\u66f4\u597d\uff0c\u662f\u5148\u5224\u65ad\u5e74\u6536\u5165\u8fd8\u662f\u5148\u5224\u65ad\u6709\u6ca1\u6709\u623f\u4ea7\u5462\uff1f\u5176\u5b9e\u57281970\u5e74\u7684\u65f6\u5019\u5c31\u6709\u4e00\u4f4d\u53eb\u6606\u5170\u7684\u5927\u725b\u4f7f\u7528\u4fe1\u606f\u8bba\u4e0a\u71b5\u7684\u6982\u5ff5\u6765\u601d\u8003\u8fc7\u8fd9\u4e2a\u95ee\u9898\uff0c\u5e76\u5728\u6b64\u57fa\u7840\u4e0a\u4f7f\u7528\u4fe1\u606f\u589e\u76ca\u8fd9\u4e2a\u6982\u5ff5\u6784\u5efa\u4e86\u51b3\u7b56\u6811\u51b3\u7b56\u7684\u8fc7\u7a0b\u3002<\/p>\n

      \u5177\u4f53\u7684\u65b9\u6cd5\u662f\uff1a\u4ece\u6839\u8282\u70b9\u5f00\u59cb\uff0c\u8ba1\u7b97\u6240\u6709\u53ef\u80fd\u7279\u5f81\u7684\u4fe1\u606f\u589e\u76ca\uff0c\u9009\u62e9\u4fe1\u606f\u589e\u76ca\u6700\u5927\u7684\u7279\u5f81\u4f5c\u4e3a\u6839\u8282\u70b9\u7684\u7279\u5f81\uff0c\u7531\u8be5\u7279\u5f81\u7684\u4e0d\u540c\u7279\u5f81\u503c\u4f5c\u4e3a\u4e0d\u540c\u7684\u5b50\u8282\u70b9\uff1b\u518d\u5bf9\u5b50\u8282\u70b9\u9012\u5f52\u8c03\u7528\u4e0a\u8ff0\u65b9\u6cd5\uff0c\u6784\u5efa\u51b3\u7b56\u6811\uff1b\u76f4\u5230\u6240\u6709\u7279\u5f81\u7684\u4fe1\u606f\u589e\u76ca\u90fd\u5f88\u5c0f\u6216\u8005\u6ca1\u6709\u7279\u5f81\u53ef\u4ee5\u9009\u62e9\u4e3a\u6b62\uff0c\u6700\u540e\u5f97\u5230\u4e00\u9897\u5b8c\u6574\u7684\u51b3\u7b56\u6811$T$\u3002<\/p>\n

      \u4e0a\u8ff0\u65b9\u6cd5\u6784\u5efa\u7684\u51b3\u7b56\u6811\u5219\u4f1a\u5982\u4e0a\u56fe\u6240\u793a\u7c7b\u4f3c\u4e8e\u7b97\u6cd5\u4e2d\u7684\u4e8c\u53c9\u6811\uff0c\u4f46\u662f\u9700\u8981\u6ce8\u610f\u7684\u662fID3\u7b97\u6cd5\u7684\u51b3\u7b56\u6811\u662f\u591a\u53c9\u6811\uff0c\u5e76\u4e14\u51b3\u7b56\u6811\u7684\u5404\u4e2a\u8282\u70b9\u4f7f\u7528\u4fe1\u606f\u589e\u76ca\u9009\u62e9\u7279\u5f81\uff0c\u7136\u540e\u9012\u5f52\u6784\u5efa\u51b3\u7b56\u6811\u3002<\/p>\n

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

      \u71b5$H(X)$\u5ea6\u91cf\u4e86\u968f\u673a\u53d8\u91cf$X$\u7684\u4e0d\u786e\u5b9a\u6027\uff1b\u6761\u4ef6\u71b5$H(Y|X)$\u5ea6\u91cf\u4e86\u77e5\u9053$X$\u4ee5\u540e$Y$\u5269\u4e0b\u7684\u4e0d\u786e\u5b9a\u6027\uff1b$H(X)-H(X|Y)$\u5ea6\u91cf\u4e86$Y$\u5728\u77e5\u9053$X$\u4e4b\u540e\u4e0d\u786e\u5b9a\u6027\u7684\u51cf\u5c11\u7a0b\u5ea6\uff0c\u8fd9\u4e2a\u5ea6\u91cf\u8bb0\u4f5c$g(Y,X)$\uff0c\u5e76\u4e14\u5728\u51b3\u7b56\u6811ID3\u7b97\u6cd5\u4e2d\u79f0\u4e3a\u4fe1\u606f\u589e\u76ca\u3002<\/p>\n

      \u4ece\u6b64\u5904\u53ef\u4ee5\u770b\u51fa\uff0c\u4fe1\u606f\u589e\u76ca\u8d8a\u5927\u7684\u7279\u5f81\uff0c$Y$\u5728\u77e5\u9053$X$\u4e4b\u540e\u4e0d\u786e\u5b9a\u6027\u7684\u51cf\u5c11\u7a0b\u5ea6\u4f1a\u8d8a\u5927\uff0c\u56e0\u6b64\u66f4\u9002\u5408\u7528\u6765\u5206\u7c7b\u3002<\/p>\n

    \u51b3\u7b56\u6811ID3\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

      ID3\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<\/strong>\uff0c\u9009\u62e9\u4fe1\u606f\u589e\u76ca<\/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\u6811ID3\u7b97\u6cd5\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. \u6ca1\u6709\u8003\u8651\u5230\u7279\u5f81\u8fde\u7eed\u503c\u7684\u60c5\u51b5\uff0c\u5373\u5982\u4eba\u7684\u8eab\u9ad8\u3001\u4f53\u91cd\u90fd\u662f\u8fde\u7eed\u503c\uff0c\u65e0\u6cd5\u5728ID3\u7b97\u6cd5\u4e2d\u5e94\u7528\uff0c\u5373ID3\u7b97\u6cd5\u66f4\u9002\u5408\u505a\u5206\u7c7b<\/li>\n
        2. \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\u56e0\u4e3a\u76f8\u540c\u6761\u4ef6\u4e0b\uff0c\u53d6\u503c\u6bd4\u8f83\u591a\u7684\u7279\u5f81\u7684\u4fe1\u606f\u589e\u76ca\u5927\u4e8e\u53d6\u503c\u8f83\u5c11\u7684\u7279\u5f81<\/li>\n
        3. \u6ca1\u6709\u8003\u8651\u8fc7\u62df\u5408\u95ee\u9898<\/li>\n
        4. \u6ca1\u6709\u8003\u8651\u7279\u5f81\u4e2d\u542b\u6709\u7f3a\u5931\u503c\u7684\u60c5\u51b5<\/li>\n<\/ol>\n

          \u5c0f\u7ed3<\/h1>\n

            \u51b3\u7b56\u6811ID3\u7b97\u6cd5\u662f\u6700\u539f\u59cb\u7684\u51b3\u7b56\u6811\u7b97\u6cd5\uff0c\u7531\u4e8e\u5b83\u8f83\u597d\u7684\u89e3\u91ca\u578b\u5728\u5f53\u65f6\u4e5f\u662f\u706b\u4e86\u4e00\u6bb5\u65f6\u95f4\u3002\u4f46\u662f\u4ed6\u7684\u7f3a\u70b9\u4e5f\u662f\u7279\u522b\u660e\u663e\u7684\uff0c\u6811\u6df1\u5ea6\u5927\u4e86\u5219\u5bb9\u6613\u8fc7\u62df\u5408\uff0c\u5e76\u4e14\u65e0\u6cd5\u5904\u7406\u56de\u5f52\u95ee\u9898\uff0c\u65e0\u6cd5\u5904\u7406\u8fde\u7eed\u503c\u7684\u95ee\u9898\u7b49\u7b49\u4e00\u7cfb\u5217\u95ee\u9898\u3002<\/p>\n

            \u51b3\u7b56\u6811ID3\u7b97\u6cd5\u7531\u4e8e\u5b83\u81ea\u8eab\u7684\u7f3a\u9677\u76ee\u524d\u5df2\u8f83\u5c11\u4f7f\u7528\uff0c\u4e5f\u56e0\u4e3a\u8fd9\u4e9b\u7f3a\u70b9\u6709\u4e86\u6211\u4eec\u4e0b\u4e00\u7bc7\u8981\u4ecb\u7ecd\u7684\u7b97\u6cd5\u2014\u2014\u51b3\u7b56\u6811C4.5\u7b97\u6cd5\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"

          \u51b3\u7b56\u6811ID3\u7b97\u6cd5   \u51b3\u7b56\u6811\uff08decision tree\uff09\u662f\u4e00\u79cd\u57fa\u672c\u7684\u5206\u7c7b\u4e0e\u56de\u5f52\u65b9\u6cd5\uff0c\u540c\u65f6 […]<\/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\/3055"}],"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=3055"}],"version-history":[{"count":0,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts\/3055\/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=3055"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3055"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3055"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}