Peng Yu wrote:
On Wed, Dec 2, 2009 at 3:51 PM, David Winsemius <dwinsem...@comcast.net> wrote:
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.
----------------------------
I didn't read Details. Because I was interested in the arguments. The
problem of some R document is that some information should gathered
together are spread into multiple places. In particular, in the help
of intersect, the first line of 'Details' should be merged with
'Argument' to make the help page clear and easy to read.
----------------------------
I take very strong exception to this suggestion and to the
whining tone of the comment. If an R user can't be bothered
to read *all* of a help page, then that's his problem, not R's.
Since it is IMHO too common in this forum to see complaints
about the documentation, let me just say this:
I personally find the documentation of (base) R very, very
good to excellent and I think that R-Core deserve a big
pat on the back for their efforts to be as informative as
possible with the help system. Probably my most used
R function is "?" and I particularly like the
arguments/details/value etc layout.
End of rant.
-Peter Ehlers
--
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
______________________________________________
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David Winsemius, MD
Heritage Laboratories
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
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PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
and provide commented, minimal, self-contained, reproducible code.
______________________________________________
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.
