Uwe Ligges <[EMAIL PROTECTED]> writes: > Charles Dupont wrote: > >> I was messing around with R and I found an example R behaving oddly: >> >> a <- alist(NULL, "bob", c(3,6,2,3)) >> a >> a == 'NULL' >> a == "NULL" >> a == 'cat' >> > > > Always use is.null() to test on NULL, as in:
What should I do if I want to check for the string "NULL"? > a <- list(NULL, "NULL", NA, "NA") > a == "NULL" [1] TRUE TRUE FALSE FALSE > a == "NA" [1] FALSE FALSE TRUE TRUE These are because of as.character: > as.character(a) [1] "NULL" "NULL" "NA" "NA" Yet, > as.character(NULL) character(0) > as.character(NA) [1] NA + seth ______________________________________________ R-devel@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-devel
