Hmmmm, well, this is theoretically possible, but I have not heard of such a virus. Yet. For now, viruses hide inside computer programs — and in the places where programs normally hang out (such as the boot sector of a floppy disk or a hard drive).
By definition, data files aren’t executable, and viruses have to be executed. It’s safest to say that viruses hide only in executable program files. But wait. . . .
Macro viruses are found in Word and Excel documents, so if this is what you mean by data files, then you’re correct. Other than this, generally viruses do not live inside data files.