Example usage for weka.filters.unsupervised.attribute AddExpression setExpression

Introduction

In this page you can find the example usage for weka.filters.unsupervised.attribute AddExpression setExpression.

Prototype

public void setExpression(String expr) 

Source Link

Document

Set the expression to apply

Usage

From source file:es.bsc.autonomic.powermodeller.tools.classifiers.WekaWrapper.java

License:Apache License

public static DataSet processDataSet(DataSet ds, VariableParser parser) {

    String independent = ds.getIndependent();

    if (independent == null)
        throw new WekaWrapperException("Independent variable is not set in dataset.");

    HashMap<String, String> expression_list = parser.getNewMetrics();
    Instances data = convertDataSetToInstances(ds);

    try {/*www  .ja  v  a2s . co m*/
        // Apply filters for all the new variables
        for (Map.Entry<String, String> entry : expression_list.entrySet()) {
            String key = entry.getKey();
            String value = entry.getValue();
            logger.debug("Generating new variable " + key + " as " + value);

            AddExpression add_filter = new AddExpression();
            add_filter.setName(key);
            add_filter.setExpression(value);
            add_filter.setInputFormat(data);

            data = useFilter(data, add_filter);

        }

    } catch (Exception e) {
        logger.error("Error while processing new variables", e);
        throw new WekaWrapperException("Error while processing new variables");
    }

    // Iterate over all the columns and keep only the ones contained in variables list
    List<String> variables = parser.getColumns();

    // Append independent variable to the list of variables to keep
    variables.add(independent);

    // Remove unneeded attributes
    try {

        // it's important to iterate from last to first, because when we remove
        // an instance, the rest shifts by one position.
        for (int i = data.numAttributes() - 1; i >= 0; i--) {
            String n = data.attribute(i).name();
            if (!variables.contains(data.attribute(i).name())) {
                logger.trace("Deleting unnecessary attribute " + data.attribute(i).name());
                data.deleteAttributeAt(i);
            }
        }

        data.toString();
    } catch (Exception e) {
        logger.error("Error while removing unneeded variables", e);
        throw new WekaWrapperException("Error while removing unneeded variables");
    }

    // Convert Instances in csv and return the new DataSet
    String new_path = CoreConfiguration.getNewCSVFileName();
    try {
        CSVSaver saver = new CSVSaver();
        saver.setInstances(data);
        saver.setFile(new File(new_path));
        saver.writeBatch();
    } catch (Exception e) {
        logger.error("Error while removing unneeded variables", e);
        throw new WekaWrapperException("Error while removing unneeded variables");
    }

    DataSet ret = new DataSet(new_path);
    ret.setIndependent(independent);
    return ret;
}

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