base (version 3.5.1)

is.R: Are we using R, rather than S?

Description

Test if running under R.

Usage

is.R()

Value

is.R returns TRUE if we are using R and FALSE otherwise.

Details

The function has been written such as to correctly run in all 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 }

See Also

R.version, system.

Examples

# NOT RUN {
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]
# }