[R] Editing Strings in R
Marc Schwartz
MSchwartz at MedAnalytics.com
Fri Jul 30 04:36:14 CEST 2004
On Thu, 2004-07-29 at 21:08, Gabor Grothendieck wrote:
> Bulutoglu Dursun A Civ AFIT/ENC <Dursun.Bulutoglu <at> afit.edu> writes:
>
> >
> > I was wondering if there is a way of editting strings in R. I
> > have a set of strings and each set is a row of numbers and paranthesis.
> > For example the first row is:
> > (0 2)(3 4)(7 9)(5 9)(1 5)
> > and I have a thousand or so such rows. I was wondering how I
> > could get the corresponding string obtained by adding 1 to all the
> > numbers in the string above.
>
> First do the 1 character translations simultaneously using chartr and
> then use gsub for the remaining one to two character translation:
>
> gsub("0","10",chartr("0123456789","1234567890","(0 2)(3 4)(7 9)(5 9)(1 5)"))
Gabor,
One problem: Multi-digit numbers in the source string:
> gsub("0","10",chartr("0123456789","1234567890",
"(10 99)(3 4)(7 9)(5 9)(1 5)"))
[1] "(21 1010)(4 5)(8 10)(6 10)(2 6)"
Note the first number "10" gets transformed to "21" and the "99" goes to
"1010".
I made a quick update to NewRow, which is not faster, but gets it to two
lines, instead of three, and is a bit cleaner:
NewRow <- function(x)
{
TempMat <- matrix(as.numeric(unlist(strsplit(x, "([\\(\\) ])"))),
ncol = 3, byrow = TRUE) + 1
paste("(", TempMat[, 2], " ", TempMat[, 3], ")", sep = "",
collapse = "")
}
Note that with multi digit numbers, it gives a correct result:
> NewRow("(10 99)(101 4)(7 9)(5 9)(1 5)")
[1] "(11 100)(102 5)(8 10)(6 10)(2 6)"
HTH,
Marc Schwartz
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