On Dec 2, 2009, at 4:33 PM, Peng Yu wrote:
intersect(c(1,3,2),c('1','3')) # note x is numeric and y is
character
[1] "1" "3"
Apparently, intersect() treats num as string. But this is not
documented in the help. Could somebody add it in the future version of
R?
It is documented that intersect will return a value of that is same
mode as its "y" argument. How could it be any more clear?
Also according to the help, the argument should not have duplicated
elements.
That's not what my help page says. It says that "conceptually" they
won't have them, but immediately thereafter it says:
"Details
Each of union, intersect, setdiff and setequal will discard any
duplicated values in the arguments, and they apply as.vector to their
arguments (and so in particular coerce factors to character vectors)."
Unfortunately, R does not have a package that will ensure that users
will read the help pages carefully.
--
David
But I tried the following example, it seems that it doesn't
matter where there are duplicated elements or not. Should the help be
corrected? Or somebody could provide me with an example that make
intersect() fails if there are duplicated elements?
x=c(3,1,2,1,7)
y=c(5,1,4,2,3,8,1)
x
[1] 3 1 2 1 7
y
[1] 5 1 4 2 3 8 1
intersect(x,y)
[1] 3 1 2
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
