Re: [R] Vector docs
Thanks for this, and all the other responses - I have a better
understanding now.
David Winsemius wrote:
On May 30, 2010, at 1:43 AM, i...@whywouldwe.com wrote:
Hi
The docs for R are very practical, which is quite refreshing compared
to other languages, however I can't find any details about all the
things I can do with a vector. I'm expecting methods like
vector.contains('foo') and vector.remove('foo'), maybe those methods
don't exist but I'd love to find a page that details the ones that do.
Since vectors may contain named elements, your request is ambiguous. I
cannot tell whether "foo" is a name or a value. It's also ambiguous
because it's not clear what vector.contains() is supposed to return.
If you read the introductory material, you should find that the
function "[" is fairly fundamental to R operations.
?"["
?which
?grep
> x <- c(foo=3,bar=4)
> x
foo bar
3 4
> x["foo"]
foo
3
> x[-"foo"]
Error in -"foo" : invalid argument to unary operator
# the negation operation on indices only works with numeric arguments
# grep and which provide numeric resutls that can be used for "removal".
> x[grep("foo", names(x))]
foo
3
> x[-grep("foo", names(x))]
bar
4
> x[which(names(x)=="foo")]
foo
3
Minus operations on numeric indices perform removal, at least to the
extent of what is returned, but indexing does not do destructive
removal unless accompanied by "<-" . In fact "[<-" is a function in
its own right.
I'd also like to find some docs about foreach loops (unless there's a
better way to iterate through a vector), I've only found mailing list
posts.
Indexed solution are preferred, so see above, but if you want to find
the help page for the "for" function
?"Control"
--
David Winsemius, MD
West Hartford, CT
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Re: [R] Vector docs
On May 30, 2010, at 1:43 AM, i...@whywouldwe.com wrote:
Hi
The docs for R are very practical, which is quite refreshing
compared to other languages, however I can't find any details about
all the things I can do with a vector. I'm expecting methods like
vector.contains('foo') and vector.remove('foo'), maybe those methods
don't exist but I'd love to find a page that details the ones that do.
Since vectors may contain named elements, your request is ambiguous. I
cannot tell whether "foo" is a name or a value. It's also ambiguous
because it's not clear what vector.contains() is supposed to return.
If you read the introductory material, you should find that the
function "[" is fairly fundamental to R operations.
?"["
?which
?grep
> x <- c(foo=3,bar=4)
> x
foo bar
3 4
> x["foo"]
foo
3
> x[-"foo"]
Error in -"foo" : invalid argument to unary operator
# the negation operation on indices only works with numeric arguments
# grep and which provide numeric resutls that can be used for "removal".
> x[grep("foo", names(x))]
foo
3
> x[-grep("foo", names(x))]
bar
4
> x[which(names(x)=="foo")]
foo
3
Minus operations on numeric indices perform removal, at least to the
extent of what is returned, but indexing does not do destructive
removal unless accompanied by "<-" . In fact "[<-" is a function in
its own right.
I'd also like to find some docs about foreach loops (unless there's
a better way to iterate through a vector), I've only found mailing
list posts.
Indexed solution are preferred, so see above, but if you want to find
the help page for the "for" function
?"Control"
--
David Winsemius, MD
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.
Re: [R] Vector docs
i...@whywouldwe.com wrote:
Hi
The docs for R are very practical, which is quite refreshing compared to
other languages, however I can't find any details about all the things I
can do with a vector. I'm expecting methods like vector.contains('foo')
and vector.remove('foo'), maybe those methods don't exist but I'd love
to find a page that details the ones that do.
I'd also like to find some docs about foreach loops (unless there's a
better way to iterate through a vector), I've only found mailing list posts.
There may be such a page somewhere, but it is probably incomplete. The
object model in R has methods owned by generics, not by classes. So
even if someone wrote a list of all methods that worked on vectors,
someone else could add a new one without modifying the vector class.
You can ask R what methods are currently visible, e.g.
library(methods)
showMethods(classes="vector")
but it won't show methods in unattached packages.
Duncan Murdoch
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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] Vector docs
Hi
The docs for R are very practical, which is quite refreshing compared to
other languages, however I can't find any details about all the things I
can do with a vector. I'm expecting methods like vector.contains('foo')
and vector.remove('foo'), maybe those methods don't exist but I'd love
to find a page that details the ones that do.
I'd also like to find some docs about foreach loops (unless there's a
better way to iterate through a vector), I've only found mailing list posts.
Thanks
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R-help@r-project.org mailing list
https://stat.ethz.ch/mailman/listinfo/r-help
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and provide commented, minimal, self-contained, reproducible code.
