>Did you support Ben's wish to allow 'symbol' (aka 'name') objects as well,
>or even more general language objects (as by the subject's wording) ?
Do you mean should match treat
match(quote(foo), list(as.name("bar"), as.name("foo"))) # error
the same as
match(list(quote(foo)), list(as.name("bar"), as.name("foo"))) # 2
? I don't think that would be good - 'x' needs to be a list or expression
in the length!=1 cases, so it should be one in all cases.
On the other hand it would be nice to fix up things like
> list(list(quote(foo)), quote(list(foo))) %in% list(quote(list(foo)))
[1] TRUE TRUE
either by using calls to identical() in the match/hashing code or
adding "quoteExpressions" when deparsing the language objects.
x <- list(list(quote(foo)), quote(list(foo)))
table <- list(quote(list(foo)))
x %in% table
#[1] TRUE TRUE
lapply(x, deparse) %in% lapply(table, deparse)
#[1] TRUE TRUE
lapply(x, deparse, control="quoteExpressions") %in% lapply(table,
deparse, control="quoteExpressions")
#[1] FALSE TRUE
duplicated() already seems to do the right thing in that case:
duplicated(x)
#[1] FALSE FALSE
duplicated(x[c(1,2,1)])
#[1] FALSE FALSE TRUE
Bill Dunlap
TIBCO Software
wdunlap tibco.com
On Wed, Aug 26, 2015 at 1:54 AM, Martin Maechler <maech...@stat.math.ethz.ch
> wrote:
> >>>>> William Dunlap <wdun...@tibco.com>
> >>>>> on Tue, 25 Aug 2015 09:47:23 -0700 writes:
>
> > match(x,table) and x%in%table work when x and table are lists of
> language
> > objects or expressions. E.g.,
>
> > expression(quote(1+2), quote(log2(16))) %in% expression(3,
> quote(1+2), c(4L,5L,6L,7L))
> > #[1] TRUE FALSE
> > list(quote(1+2), quote(log2(16))) %in% list(3, quote(1+2),
> c(4L,5L,6L,7L))
> > #[1] TRUE FALSE
> > match(list(quote(1+2), quote(log2(16))), list(3, quote(1+2),
> c(4L,5L,6L,7L)))
> > #[1] 2 NA
>
> yes, or slightly more naturally for the first case,
>
> > expression(1+2, log2(16)) %in% expression(3, 1+2, c(4L,5L,6L,7L))
> [1] TRUE FALSE
>
>
> > With your example data:
> > spList[1] %in% spList
> > #[1] TRUE
> > list(quote(foo)) %in% spList
> > #[1] TRUE
> > list(quote(nosuchsymbol)) %in% spList
> > #[1] FALSE
>
> yes indeed, that works because list()s and expression()s are
> "vector"s in the wide sense, as "we all" know.
>
> Did you support Ben's wish to allow 'symbol' (aka 'name') objects as well,
> or even more general language objects (as by the subject's wording) ?
>
> Internally, in these cases the matches do happen with character
> coerced objects eventually; still I'd tend to agree that allowing some of
> these as arguments to match() in addition to the
> wide-sense-vectors (and NULL !) would make sense.
>
> Martin
>
>
>
> > Bill Dunlap
> > TIBCO Software
> > wdunlap tibco.com
>
> > On Tue, Aug 25, 2015 at 9:12 AM, Ben Bolker <bbol...@gmail.com>
> wrote:
>
> >> -----BEGIN PGP SIGNED MESSAGE-----
> >> Hash: SHA1
> >>
> >>
> >> I haven't yet dug into the internals of match() yet to see what's
> >> going on, but I'm wondering whether there's a design reason why I
> >> can't use %in% (which is a wrapper for match()) on language objects.
> >>
> >> I'd like to test whether a language object is in a list of language
> >> objects, but I get the error "'match' requires vector arguments":
> >>
> >> specials <- c("foo","bar")
> >> spList <- lapply(specials,as.name) ## convert to language objects
> >> "a" %in% spList ## works (FALSE)
> >> spList[[1]] %in% spList ## 'match' requires vector arguments
> >> quote(foo) %in% spList ## ditto
> >> quote(foo) == spList[[1]] ## TRUE
> >>
> >> obviously I can go the other way, converting my target into text:
> >>
> >> deparse(spList[[1]]) %in% specials ## TRUE
> >>
> >> I could also write my own function to loop through the list and stop
> >> when I find it. But I'd prefer to use built-in functionality if
> possible.
> >>
> >> Does anyone have any clues/see what I'm missing?
> >>
> >> cheers
> >> Ben Bolker
> >> -----BEGIN PGP SIGNATURE-----
> >> Version: GnuPG v1.4.11 (GNU/Linux)
> >>
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> >> =w3OR
> >> -----END PGP SIGNATURE-----
> >>
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> >>
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