我正在尝试将更多实例添加到我的训练集中，并执行10倍交叉验证。
我的实例为String格式，因此我使用StringToWordVector过滤器将其转换为数字。如果我不添加我想要的多余页面，事情将会很好。但是当我添加命令trainSet.addAll(data2);并将trainSet传递到过滤器时，在IndexOutOfBoundsException的第一次迭代中得到了一个奇怪的Instances fTrainSet = Filter.useFilter(trainSet, filter);
Instances data = getDataFromFile("pathtofile.arff");//main dataset 1821 instances
Instances data2 = getDataFromFile("anotherpath.arff");//709 instances i want to add
int folds = 10;
for(int i=0;i<folds;i++){
Instances trainSet = data.trainCV(folds, i);//training set
System.out.println(trainSet.numInstances());//Prints 1638
Instances testSet = data.testCV(folds, i);//testing set
//add more instances
trainSet.addAll(data2);
System.out.println(trainSet.numInstances());//Prints 2347
//filter
StringToWordVector filter = new StringToWordVector();
filter.setInputFormat(trainSet);
filter.setWordsToKeep(10000);
filter.setTFTransform(true);
filter.setLowerCaseTokens(true);
filter.setOutputWordCounts(true);
Stemmer stemmer = new IteratedLovinsStemmer();
filter.setStemmer(stemmer);
WordsFromFile stopwords = new WordsFromFile();
stopwords.setStopwords(new File(".data/stopwords2.txt"));
filter.setStopwordsHandler(stopwords);
Instances fTrainSet = Filter.useFilter(trainSet, filter);//error!!!
Instances fTestSet = Filter.useFilter(testSet, filter);
....
//classification and evaluation....
尝试使用过滤器时出现以下错误：
Exception in thread "main" java.lang.IndexOutOfBoundsException: Index: 2161, Size: 1749
at java.util.ArrayList.rangeCheck(Unknown Source)
at java.util.ArrayList.get(Unknown Source)
at weka.core.Attribute.addStringValue(Attribute.java:924)
at weka.core.StringLocator.copyStringValues(StringLocator.java:150)
at weka.core.StringLocator.copyStringValues(StringLocator.java:91)
at weka.filters.Filter.copyValues(Filter.java:399)
at weka.filters.Filter.bufferInput(Filter.java:342)
at weka.filters.unsupervised.attribute.StringToWordVector.input(StringToWordVector.java:655)
at weka.filters.Filter.useFilter(Filter.java:692)
at CrossValidationExample.main(CrossValidationExample.java:108)
有什么事吗
最佳答案
经过一番搜索后，我意识到addAll函数有问题。我能想到的一个原因是addAll仅添加实例的引用，当我尝试将它们与filter一起使用时，这是一个问题。
相反，我使用了此处建议的合并功能https://stackoverflow.com/a/12359788/3923800，因此我用trainSet.addAll(data2);替换了Instances newTrainSettrainSet = merge(trainSet,data2);，并且一切正常。