on 06/21/2008 09:18 AM Gabor Grothendieck wrote:
On Sat, Jun 21, 2008 at 8:31 AM, Wacek Kusnierczyk
<[EMAIL PROTECTED]> wrote:
Hans-Jörg Bibiko wrote:
On 21.06.2008, at 01:36, Ken Liu wrote:
I would like to convert a character vector
xxx <- c("1/2", "1/4")
to
yyy <- c(0.5, 0.25)
, but as.numeric didn't work for me. Could anyone give me a hint
please?
There are many many ways, and they're depending on the structure of
xxx. If you only have such fractions you can use this naïve approach:
as.numeric( gsub("(\\d+)/(\\d+)", "\\1", xxx, perl=T) ) / as.numeric(
gsub("(\\d+)/(\\d+)", "\\2", xxx, perl=T) )
or:
library(gsubfn)
as.numeric(
gsubfn("([0-9]+)/([0-9]+)",
numerator+denominator~as.numeric(numerator)/as.numeric(denominator),
xxx, backref=-2)
)
strapply, also in the gsubfn package, could be used here in a similar way too:
library(gsubfn)
strapply(xxx, "([0-9]+)/([0-9]+)", ~ as.numeric(x) / as.numeric(y), backref =
-2, simplify = c)
[1] 0.50 0.25
or
fn$sapply(strapply(xxx, "[0-9]+", as.numeric), ~ x[1]/x[2])
[1] 0.50 0.25
I may have missed this one in the thread someplace, but I did not note
any solutions based upon using strsplit(). So:
> sapply(strsplit(xxx, split = "/"),
function(x) as.numeric(x[1]) / as.numeric(x[2]))
[1] 0.50 0.25
or
> apply(sapply(strsplit(xxx, split = "/"), as.numeric),
2, function(x) x[1] / x[2])
[1] 0.50 0.25
HTH,
Marc Schwartz
______________________________________________
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.
