The prefix.suffix readings of a dotted R name, longest prefix first, which is the order S3 dispatch resolves them in (as.data.frame.matrix reads as as.data.frame before as.data).
prefix.suffix
as.data.frame.matrix
as.data.frame
as.data
The
prefix.suffixreadings of a dotted R name, longest prefix first, which is the order S3 dispatch resolves them in (as.data.frame.matrixreads asas.data.framebeforeas.data).