system.dataset.updateRow(dataset, rowIndex, changes)
Dataset dataset - The starting dataset. Will not be modified (datasets are immutable), but acts as the basis for the returned dataset.
int rowIndex - The index of the row to update (starting at 0)
PyDictionary changes - A Dictionary of changes to make. They keys in the dictionary should match column names in the dataset, and their values will be used to update the row.
Dataset - A new dataset with the values at the specified row updated according to the values in the dictionary.