assign, documentation (PR#1434)
On Thu, Apr 04, 2002 at 05:37:18PM +0200, Peter Dalgaard BSA wrote:
ripley@stats.ox.ac.uk writes:
On Thu, 4 Apr 2002 Martin.Schlather@uni-bayreuth.de wrote:
The help for `assign' says
In all the assignment operator expressions, `x' can be a name or
an expression defining a part of an object to be replaced (e.g.,
`z[[1]]'). The name does not need to be quoted, though it can be.
So I would expect that by
a<-1:4
assign("a[1]",2)
the first component of a gets the value 2, but the object "a[1]" is
created.
Could this be clarified in the documentation?
Could you suggest how? You quoted an *expression*, and the page refers to quoting a *name*, so I don't know that I see the crux here.
Actually, it *is* a name that is getting quoted, it just has these weird bracket characters in it, so it is not "syntactically valid". One improvement might be: "the name can be any string of text and may be quoted, but this is only necessary if it is not a syntactically valid name."
I think the original point was that he expected that a[1] would be
changed not that a new variable named "a[1]" would be created. I
don't think your suggestion will help with this. I think that Brian
is correct, unless of course you want to spend some amount of time
figuring out the logic/parsing requirements.
"Assign treats the quoted string as a symbol, it does not parse it in
any way", might help. On the otherhand, in some large number of
years this is the first person who has had this problem, I'm not
sure we should be documenting for less than 1% of the population
unless of course,
"we are trying to be as accurate as possible without regard to
readability" :-), to quote the views of a certain member of R core
on documentation.
We might also emphasize that "assignment operator expressions" does not include assign(), only <-, <<-, and =. (And _ until we finally get it killed...). On the other hand it is arguably clear enough already, if read carefully. (For this reason alone, the posters remark is off base, but he might have asked about "a[1]" <- 2.) In assign(), `x' must be a character object. As in
a <- "b" assign(a,2) a
[1] "b"
b
[1] 2 -- O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - (p.dalgaard@biostat.ku.dk) FAX: (+45) 35327907 -.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.-.- r-devel mailing list -- Read http://www.ci.tuwien.ac.at/~hornik/R/R-FAQ.html Send "info", "help", or "[un]subscribe" (in the "body", not the subject !) To: r-devel-request@stat.math.ethz.ch _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._
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