The .iloc and .loc indexers each select data by either integer or label location but are not able to handle a combination of both input types at the same time. In earlier versions of pandas, another indexer, .ix, was available to select data by both integer and label location. While this conveniently worked for those specific situations, it was ambiguous by nature and was a source of confusion for many pandas users. The .ix indexer has subsequently been deprecated and thus should be avoided.