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Add label to existing ExampleSet

Hi,
I have an existing example set. How can I effectively add a label attribute to the existing example set?


ExampleSet newExampleSet = .... (an existing example set);

// ADD LABEL ATTRIBUTE
Attribute label = AttributeFactory.createAttribute("label", Ontology.NOMINAL);
newExampleSet.getAttributes().setLabel(label);

// SET NOMINAL VALUE
Example e = newExampleSet.getExample(0);
e.setLabel(label.getMapping().mapString(clsName));

throws java.lang.ArrayIndexOutOfBoundsException: -1 on the last line.


	SEVERE: Process failed: operator cannot be executed (-1). Check the log messages...
	java.lang.ArrayIndexOutOfBoundsException: -1
	at com.rapidminer.example.table.DoubleArrayDataRow.set(DoubleArrayDataRow.java:52)
	at com.rapidminer.example.table.AbstractAttribute.setValue(AbstractAttribute.java:184)
	at com.rapidminer.example.table.DataRow.set(DataRow.java:85)
	at com.rapidminer.example.Example.setValue(Example.java:140)
	at com.rapidminer.example.Example.setLabel(Example.java:178)
	at ... last code of the example above ...

Thanks in advance for any help,
radone

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Marco_Boeck

Hi,

this should work:


Attribute newAtt = AttributeFactory.createAttribute("label", Ontology.NOMINAL);
newExampleSet.getExampleTable().addAttribute(newAtt);
newExampleSet.getAttributes().addRegular(newAtt);
newExampleSet.getAttributes().setSpecialAttribute(newExampleSet.getAttributes().get("label"), "label");

There are other ways, but this one should work just fine.

Regards,
Marco

radone

Thank you for your reply.

Unfortunately, ended with exactly the same error. I got some debugging info about the just inserted label and it seems that "-1" in my outpput might have something to do with my problem?


String clsName = "MY_NEW_NOMINAL_CLASS";
ExampleSet newExampleSet = .... (an existing example set);

// ADD LABEL ATTRIBUTE
Attribute label = AttributeFactory.createAttribute("label", Ontology.NOMINAL);
newExampleSet.getAttributes().setLabel(label);

System.out.println(newExampleSet.getAttributes().getLabel());

// SET NOMINAL VALUE
Example e = newExampleSet.getExample(0);
e.setLabel(label.getMapping().mapString(clsName));

the system out gives:

#-1: label (nominal/single_value)/values=[]

and the code:


                Example e = newExampleSet.getExample(0);
		e.setLabel(label.getMapping().mapString(clsName));

throws:

SEVERE: Process failed: operator cannot be executed (-1). Check the log messages...
java.lang.ArrayIndexOutOfBoundsException: -1
	at com.rapidminer.example.table.DoubleArrayDataRow.set(DoubleArrayDataRow.java:52)
	at com.rapidminer.example.table.AbstractAttribute.setValue(AbstractAttribute.java:184)
	at com.rapidminer.example.table.DataRow.set(DataRow.java:85)
	at com.rapidminer.example.Example.setValue(Example.java:140)
	at com.rapidminer.example.Example.setLabel(Example.java:178)
	at .... last code of the example above ....

Marco_Boeck

Hi,

I forgot a line in my first reply, so I had to edit it. If you copy that codeblock, you should be fine.
Note that to be able to use

newExampleSet.getAttributes().setLabel(label);

the label attribute must already be present in the attribute set.

Regards,
Marco

radone

Thank you Marco.

The line:

newExampleSet.getExampleTable().addAttribute(newAtt);

was exactly what I was missing.