"Get and set values using Groovy Script"

wessel

Dear All,

I want to learn how to use groovy script.

How to get example values for a particular attribute?
and how to set example values for a particular attribute?

The example by Ingo, pasted below only shows how to iterate over all attributes and all examples.
This is nice, but what if you only want to iterate over all examples of attribute 1,
calculate the sum, and place the result in attribute 2?
How to do this?

Like you start with:

att1 att2
0.1 NaN
0.2 NaN
0.3 NaN
0.4 NaN

And the result will be:
att1 att2
0.1 0.1
0.2 0.3
0.3 0.6
0.4 1.0

Best regards,

Wesesl

ExampleSet exampleSet = operator.getInput(ExampleSet.class);

exampleSet.recalculateAllAttributeStatistics();

for (Attribute attribute : exampleSet.getAttributes()) {
    double mean = exampleSet.getStatistics(attribute, Statistics.AVERAGE);
    String name = attribute.getName();
    for (Example example : exampleSet) {
        example[name] = example[name] - mean;
    }
}

return exampleSet;

colo

Hi wessel,

I guess you don't have the tutorial for the extension development at hand. This starts with an example for using the script operator. Since the other existing documentation is very rare, I built a little process for your example (just containing other values). I added a third attribute to demonstrate the creation of new attributes. The whole process is appended to the end of the post, here comes just the content of the script operator:

import com.rapidminer.tools.Ontology;

ExampleSet exampleSet = input[0];

Attributes attributes = exampleSet.getAttributes();
Attribute att1 = attributes.get("att1");
Attribute att2 = attributes.get("att2");

// generate additional attribute
Attribute att3 = AttributeFactory.createAttribute("att3", Ontology.REAL);
// add new attribute to example set
attributes.addRegular(att3);
// insert new column into example set's data table
exampleSet.getExampleTable().addAttribute(att3);

double sum = 0.0;

for (Example example : exampleSet) {
	double currentValue = example.getValue(att1);
	sum += currentValue;
	example.setValue(att2, sum);
	example.setValue(att3, sum);
}

return exampleSet;

I hope this makes things a bit clearer.

Best regards
Matthias

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<process version="5.1.008">
  <context>
    <input/>
    <output/>
    <macros/>
  </context>
  <operator activated="true" class="process" compatibility="5.1.008" expanded="true" name="Process">
    <process expanded="true" height="116" width="547">
      <operator activated="true" class="generate_data" compatibility="5.1.008" expanded="true" height="60" name="Generate Data" width="90" x="45" y="30">
        <parameter key="number_examples" value="5"/>
        <parameter key="number_of_attributes" value="2"/>
        <parameter key="attributes_lower_bound" value="0.0"/>
      </operator>
      <operator activated="true" class="select_attributes" compatibility="5.1.008" expanded="true" height="76" name="Select Attributes" width="90" x="179" y="30">
        <parameter key="attribute_filter_type" value="single"/>
        <parameter key="attribute" value="label"/>
        <parameter key="invert_selection" value="true"/>
        <parameter key="include_special_attributes" value="true"/>
      </operator>
      <operator activated="true" class="loop_examples" compatibility="5.1.008" expanded="true" height="76" name="Loop Examples" width="90" x="313" y="30">
        <process expanded="true" height="607" width="740">
          <operator activated="true" class="set_data" compatibility="5.1.008" expanded="true" height="76" name="Set Data" width="90" x="45" y="30">
            <parameter key="example_index" value="%{example}"/>
            <parameter key="attribute_name" value="att2"/>
            <parameter key="value" value="NaN"/>
            <list key="additional_values"/>
          </operator>
          <connect from_port="example set" to_op="Set Data" to_port="example set input"/>
          <connect from_op="Set Data" from_port="example set output" to_port="example set"/>
          <portSpacing port="source_example set" spacing="0"/>
          <portSpacing port="sink_example set" spacing="0"/>
          <portSpacing port="sink_output 1" spacing="0"/>
        </process>
      </operator>
      <operator activated="true" class="execute_script" compatibility="5.1.008" expanded="true" height="76" name="Execute Script" width="90" x="447" y="30">
        <parameter key="script" value="import com.rapidminer.tools.Ontology;&#10;&#10;ExampleSet exampleSet = input[0];&#10;&#10;Attributes attributes = exampleSet.getAttributes();&#10;Attribute att1 = attributes.get(&quot;att1&quot;);&#10;Attribute att2 = attributes.get(&quot;att2&quot;);&#10;&#10;// generate additional attribute&#10;Attribute att3 = AttributeFactory.createAttribute(&quot;att3&quot;, Ontology.REAL);&#10;// add new attribute to example set&#10;attributes.addRegular(att3);&#10;// insert new column into example set's data table&#10;exampleSet.getExampleTable().addAttribute(att3);&#10;&#10;double sum = 0.0;&#10;&#10;for (Example example : exampleSet) {&#10;&#9;double currentValue = example.getValue(att1);&#10;&#9;sum += currentValue;&#10;&#9;example.setValue(att2, sum);&#10;&#9;example.setValue(att3, sum);&#10;}&#10;&#10;return exampleSet;"/>
      </operator>
      <connect from_op="Generate Data" from_port="output" to_op="Select Attributes" to_port="example set input"/>
      <connect from_op="Select Attributes" from_port="example set output" to_op="Loop Examples" to_port="example set"/>
      <connect from_op="Loop Examples" from_port="example set" to_op="Execute Script" to_port="input 1"/>
      <connect from_op="Execute Script" from_port="output 1" to_port="result 1"/>
      <portSpacing port="source_input 1" spacing="0"/>
      <portSpacing port="sink_result 1" spacing="0"/>
      <portSpacing port="sink_result 2" spacing="0"/>
    </process>
  </operator>
</process>