我正在尝试从一个CSV数据文件生成一个.arff文件。我对Weka完全是新手，刚开始使用它才一天。我正在尝试一个简单的Twitter情感分析作为起点。我已经生成了CSV格式的训练数据。CSV文件的内容如下：

  tweet,affinScore,polarity ATAUTHORcfoblog is giving away a $25 Amex gift card (enter to win over $600 in prizes!) http://t.co/JD8EP14c ,4,4"American Express has always been my dark horse acquirer of  ATAUTHORFoursquare. Bundle in Square-like payments & its a lite-retailer platform, no? ",0,1African-American Demos Express Ethnic Identity Differently http://t.co/gInv4bKj via  ATAUTHORmediapost ,0,3Google ???????? Visa ? American Express  http://t.co/eEZTSiHY ,0,4Secrets to Success from Small-Business Owners : Lifestyle :: American Express OPEN Forum http://t.co/b85F8JX0 via  ATAUTHOROpenForum ,2,1RT  ATAUTHORhunterwalk: American Express has always been my dark horse acquirer of  ATAUTHORFoursquare. Bundle in Square-like payments & its a lite ... ,0,1Winning Surveys $1500 american express Huggies Sweeps http://t.co/WoaTFowp ,4,1I root for Square mostly because a small business that takes Square is also one that takes American Express. ,0,1I dont know how bitch be acting American Express but they cards be saying DEBIT ON IT HAVE A ?? PLEASE!!! ,-5,2Uh oh... RT  ATAUTHORBlackArrowBella: I dont know how bitch be acting American Express but they cards be saying DEBIT ON IT HAVE A ?? PLEASE!!! ,-5,2Just got another credit card. A Blue Sky card with American Express. Its gonna help pay for the honeymoon!  ATAUTHORAmericanExpress ,-1,1Follow  ATAUTHORShaveMagazine and ReTweet this msg to be entered to #Win an American Express Gift card. Winners contacted bi-weekly by direct msg! ,2,4American Express Gold zakelijk aanvragen: http://t.co/xheZwmbt ,0,3RT  ATAUTHORhunterwalk: American Express has always been my dark horse acquirer of  ATAUTHORFoursquare. Bundle in Square-like payments & its a lite ... ,0,1

这里的第一个属性是实际的推文，第二个是AFFIN分数，第三个是实际的分类类别（1-积极，2-消极，3-中性，4-垃圾信息）

现在我尝试使用以下代码从中生成.arff格式：

import weka.core.Instances;import weka.core.converters.ArffSaver;import weka.core.converters.CSVLoader;import java.io.File;public class CSV2Arff {  /**   * takes 2 arguments:   * - CSV input file   * - ARFF output file   */  public static void main(String[] args) throws Exception {    if (args.length != 2) {      System.out.println("\nUsage: CSV2Arff <input.csv> <output.arff>\n");      System.exit(1);    }    // load CSV    CSVLoader loader = new CSVLoader();    loader.setSource(new File(args[0]));    Instances data = loader.getDataSet();    // save ARFF    ArffSaver saver = new ArffSaver();    saver.setInstances(data);    saver.setFile(new File(args[1]));    saver.setDestination(new File(args[1]));    saver.writeBatch();  }}

这会生成一个看起来像这样的.arff文件：

   @relation file@attribute tweet {_ATAUTHORcfoblog_is_giving_away_a_$25_Amex_gift_card_(enter_to_win_over_$600_in_prizes!)_http://t.co/JD8EP14c_,'American_Express_has_always_been_my_dark_horse_acquirer_of__ATAUTHORFoursquare._Bundle_in_Square-like_payments_&_its_a_lite-retailer_platform,_no?_',African-American_Demos_Express_Ethnic_Identity_Differently_http://t.co/gInv4bKj_via__ATAUTHORmediapost_,Google_????????_Visa_?_American_Express__http://t.co/eEZTSiHY_,Secrets_to_Success_from_Small-Business_Owners_:_Lifestyle_::_American_Express_OPEN_Forum_http://t.co/b85F8JX0_via__ATAUTHOROpenForum_,RT__ATAUTHORhunterwalk:_American_Express_has_always_been_my_dark_horse_acquirer_of__ATAUTHORFoursquare._Bundle_in_Square-like_payments_&_its_a_lite_..._@data_ATAUTHORcfoblog_is_giving_away_a_$25_Amex_gift_card_(enter_to_win_over_$600_in_prizes!)_http://t.co/JD8EP14c_,4,4'American_Express_has_always_been_my_dark_horse_acquirer_of__ATAUTHORFoursquare._Bundle_in_Square-like_payments_&_its_a_lite-retailer_platform,_no?_',0,1African-American_Demos_Express_Ethnic_Identity_Differently_http://t.co/gInv4bKj_via__ATAUTHORmediapost_,0,3Google_????????_Visa_?_American_Express__http://t.co/eEZTSiHY_,0,4Secrets_to_Success_from_Small-Business_Owners_:_Lifestyle_::_American_Express_OPEN_Forum_http://t.co/b85F8JX0_via__ATAUTHOROpenForum_,2,1RT__ATAUTHORhunterwalk:_American_Express_has_always_been_my_dark_horse_acquirer_of__ATAUTHORFoursquare._Bundle_in_Square-like_payments_&_its_a_lite_..._,0,1

我对Weka是新手，但从我所读到的内容来看，我怀疑这个ARFF文件的格式可能不正确。有人可以对此发表评论吗？

如果格式不对，有人能指出我具体错在哪里吗？

回答：

请确保将tweet属性的类型设置为任意字符串，而不是默认的分类属性。这样做是因为如果不这样设置，每条推文的副本都会被放入类型定义中，这会导致扩展性问题。

请注意，对于推文内容的实际分析，你可能需要进一步预处理。你可能会想要使用文本的稀疏向量表示，而不是长字符串。