/**
* Returns the number of distinct values of a given attribute. Returns the number of instances if
* the attribute is a string attribute. The value 'missing' is not counted.
*
* @param attIndex the attribute (index starts with 0)
* @return the number of distinct values of a given attribute
*/
public int numDistinctValues(int attIndex) {
MyAttribute att = getAttribute(attIndex);
if (att.isContinuous()) {
double[] attVals = attributeToDoubleArray(attIndex);
Utilities.mergeSort(attVals, attVals.length);
double prev = 0;
int counter = 0;
for (int i = 0; i < size(); i++) {
if (attVals[i] == Double.NaN) {
break;
}
if ((i == 0) || (attVals[i] > prev)) {
prev = attVals[i];
counter++;
}
}
return counter;
} else {
return att.numValues();
}
}
