Hi,
> class(as(1:4, "numeric"))
[1] "integer"
Surprising but an explanation could be that an integer
vector being a particular case of numeric vector, this
coercion has nothing to do because 1:4 is already numeric.
And indeed:
> is.numeric(1:4)
[1] TRUE
> is.numeric(as(1:4, "numeric"))
[1] TRUE
However, 'as(1:4, "numeric")' is inconsistent with
> class(as.numeric(1:4))
[1] "numeric"
And, even more confusing, if you look at the coerce,ANY,numeric
method:
> selectMethod("coerce", c("integer", "numeric"))
Method Definition:
function (from, to, strict = TRUE)
{
value <- as.numeric(from)
if (strict)
attributes(value) <- NULL
value
}
<environment: namespace:methods>
Signatures:
from to
target "integer" "numeric"
defined "ANY" "numeric"
it calls as.numeric()!
So how can 'as(1:4, "numeric")' not return the same thing as
'as.numeric(1:4)' looks like a mystery to me. Could it be
conceivable that I found a bug?
Cheers,
H.
> sessionInfo()
R version 2.11.0 Under development (unstable) (2010-03-15 r51282)
x86_64-unknown-linux-gnu
locale:
[1] LC_CTYPE=en_CA.UTF-8 LC_NUMERIC=C
[3] LC_TIME=en_CA.UTF-8 LC_COLLATE=en_CA.UTF-8
[5] LC_MONETARY=C LC_MESSAGES=en_CA.UTF-8
[7] LC_PAPER=en_CA.UTF-8 LC_NAME=C
[9] LC_ADDRESS=C LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_CA.UTF-8 LC_IDENTIFICATION=C
attached base packages:
[1] stats graphics grDevices utils datasets methods base
--
Hervé Pagès
Program in Computational Biology
Division of Public Health Sciences
Fred Hutchinson Cancer Research Center
1100 Fairview Ave. N, M2-B876
P.O. Box 19024
Seattle, WA 98109-1024
E-mail: hpa...@fhcrc.org
Phone: (206) 667-5791
Fax: (206) 667-1319
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