public String getDataAt(int index) {
if (levels == null || levels.getLength() == 0) {
return RRuntime.STRING_NA;
} else {
int val = ((RIntVector) vector).getDataAt(index);
if (!vector.isComplete() && RRuntime.isNA(val)) {
return RRuntime.STRING_NA;
} else {
String l = levels.getDataAt(val - 1);
if (!levels.isComplete() && RRuntime.isNA(l)) {
return "NA"; // for comparison
} else {
return l;
}
}
}
}
