A Question on lowess() function

I used y<-x[!is.na(x)] to get rid of NA and NaN. But I don't know how to get
rid of Inf.

y<-x[is.finite(x)]   # remove NA,NaN,and Inf all at once

Also, is there more detailed info about loess() than help(loess)?

help(loess) offers a references to the literature. It doesn't get much more 
detailed than papers in scholarly journals and books.

Dirk

Wishful thinking can dominate much of the work of a profession for a decade,
but not indefinitely.   -- Robert Shiller, on Efficient Markets models, 2002