开创了WEKA的Java API一个字符串属性 [英] creating a string attribute in weka java API

问题描述

所以我想用WEKA的Java API来创建一个新的字符串属性...

so I'm trying to create a new string Attribute using weka's java API...

通过API的javadoc读书，看来，这样做的方法是使用这个构造：

reading through the API javadocs, it appears that the way to do so is to use this constructor:

Attribute

public Attribute(java.lang.String attributeName,
                 FastVector attributeValues)

    Constructor for nominal attributes and string attributes. If a null vector of attribute values is passed to the method, the attribute is assumed to be a string.

    Parameters:
        attributeName - the name for the attribute
        attributeValues - a vector of strings denoting the attribute values. Null if the attribute is a string attribute.

但我坚持因为我应该传递到attributeValues​​参数是什么......

but I'm stuck as to what I should pass into the attributeValues parameter...

当我把空，Java的抱怨受保护对象的结果
当我把空，它的语法错误结果
当我把在新FastVector（），就变成了名义上的属性是空的，而不是一个字符串属性...结果
当我创建一个新的对象：

when I put in null, Java complains about protected objects
when I put in Null, it's syntax error
when I put in new FastVector(), it becomes a nominal attribute that is empty rather than a string attribute...
when I create a new object:

FastVector fv = new FastVector();
fv.addElement(null);

再通入FV的说法，它返回一个空指针异常...

and then pass fv into the argument, it returns a null pointer exception...

究竟应该怎么投入attributeValues​​参数，使之成为一个字符串属性？

what exactly should I put into the attributeValues argument so that it becomes a string attribute?

推荐答案

您必须空转换为FastVector。否则，更多的方法将适用于方法签名：

You have to cast the null to FastVector. Otherwise more methods would apply to the method signature:

    FastVector attributes = new FastVector();
    attributes.addElement(new Attribute("attr", (FastVector) null));

下面是动态创建实例的一个很好的资源：<一href=\"http://weka.wikispaces.com/Creating+an+ARFF+file\">http://weka.wikispaces.com/Creating+an+ARFF+file

Here is a good resource for creating Instances on the fly: http://weka.wikispaces.com/Creating+an+ARFF+file

这篇关于开创了WEKA的Java API一个字符串属性的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！