title: How to map XGBoost predictions to the corresponding data rows?
body: <p>XGBoost generates a list of predictions for the test dataset. My question is how can I map the generated predictions to the actual test file rows ? Is it strictly safe to assume that the nth prediction corresponds to the nth data row ? XGBoost leverages multi-threading for its operations. So, in such a setting can it be trusted that the prediction results strictly map to the test data rows ? Ideally would have really loved if there was a way to annotate the predictions with some row identifier from the test data file ? </p>
  
  <p>I am using this example and working with DMatrix data format of XGBoost. <a href="https://github.com/dmlc/xgboost/tree/master/demo/binary_classification" rel="nofollow">https://github.com/dmlc/xgboost/tree/master/demo/binary_classification</a></p>