nd4j-backends/nd4j-api-parent/nd4j-api/src/main/java/org/nd4j/linalg/dataset/api/DataSetUtil.java
public static Pair<INDArray, INDArray> mergeLabels(INDArray[] labelsToMerge, INDArray[] labelMasksToMerge) {
        int rankFeatures = labelsToMerge[0].rank();

        switch (rankFeatures) {
            case 2:
                return DataSetUtil.merge2d(labelsToMerge, labelMasksToMerge);
            case 3:
                return DataSetUtil.mergeTimeSeries(labelsToMerge, labelMasksToMerge);
            case 4:
                return DataSetUtil.merge4d(labelsToMerge, labelMasksToMerge);
            default:
                throw new ND4JIllegalStateException("Cannot merge examples: labels rank must be in range 2 to 4"
                                + " inclusive. First example features shape: "
                                + Arrays.toString(labelsToMerge[0].shape()));
        }
    }
public static Pair<INDArray, INDArray> mergeLabels(INDArray[] labelsToMerge, INDArray[] labelMasksToMerge) {
        int rankFeatures = labelsToMerge[0].rank();

        switch (rankFeatures) {
            case 2:
                return DataSetUtil.merge2d(labelsToMerge, labelMasksToMerge);
            case 3:
                return DataSetUtil.mergeTimeSeries(labelsToMerge, labelMasksToMerge);
            case 4:
                return DataSetUtil.merge4d(labelsToMerge, labelMasksToMerge);
            default:
                throw new ND4JIllegalStateException("Cannot merge examples: labels rank must be in range 2 to 4"
                                + " inclusive. First example features shape: "
                                + Arrays.toString(labelsToMerge[0].shape()));
        }
    }
public static Pair < INDArray , INDArray > mergeLabels ( INDArray [ ] labelsToMerge , INDArray [ ] labelMasksToMerge ) { int rankFeatures = labelsToMerge [ 0 ] . rank ( ) ; switch ( rankFeatures ) { case 2 : return DataSetUtil . merge2d ( labelsToMerge , labelMasksToMerge ) ; case 3 : return DataSetUtil . mergeTimeSeries ( labelsToMerge , labelMasksToMerge ) ; case 4 : return DataSetUtil . merge4d ( labelsToMerge , labelMasksToMerge ) ; default : throw new ND4JIllegalStateException ( "Cannot merge examples: labels rank must be in range 2 to 4" + " inclusive. First example features shape: " + Arrays . toString ( labelsToMerge [ 0 ] . shape ( ) ) ) ; } }
Merge the specified labels and label mask arrays (i.e., concatenate the examples)

@param labelsToMerge     Features to merge
@param labelMasksToMerge Mask arrays to merge. May be null
@return Merged features and mask. Mask may be null
Merge the specified labels and label mask arrays ( i . e . concatenate the examples )