is.R {base} | R Documentation |
Test if running under R.
is.R()
The function was been written ca 2007 such as to correctly run in all
historical versions of R, S and S-PLUS.
In order for code to be runnable in both R and S dialects previous to
S-PLUS 8.0, your code must either define is.R
or use it as
if (exists("is.R") && is.function(is.R) && is.R()) {
## R-specific code
} else {
## S-version of code
}
(and this will only work if all of the code is parseable under all possible dialects).
Note that it does not actually demonstrate that it is being run under R, rather that is not being run under a long-obsolete version of S or S-PLUS. It will be deprecated in future versions of R.
is.R
returns TRUE
if we are using R and FALSE
otherwise.
x <- stats::runif(20); small <- x < 0.4
## In the early years of R, 'which()' only existed in R:
if(is.R()) which(small) else seq(along = small)[small]
## but it would have been better to test if 'which' existed.