| function {base} | R Documentation |
Function Definition
Description
These functions provide the base mechanisms for defining new functions in the R language.
Usage
function( arglist ) expr
return(value)
Arguments
arglist |
Empty or one or more name or name=expression terms. |
value |
An expression. |
Details
In R (unlike S) the names in an argument list cannot be quoted non-standard names.
If value is missing, NULL is returned. If it is a
single expression, the value of the evaluated expression is returned.
If the end of a function is reached without calling return, the
value of the last evaluated expression is returned.
Warning
Prior to R 1.8.0, value could be a series of non-empty
expressions separated by commas. In that case the value
returned is a list of the evaluated expressions, with names set to
the expressions where these are the names of R objects. That is,
a=foo() names the list component a and gives it value
the result of evaluating foo().
This has been deprecated (and a warning is given), as it was never documented in S, and whether or not the list is named differs by S versions.
References
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth \& Brooks/Cole.
See Also
args and body for accessing the arguments
and body of a function.
debug for debugging; invisible for
return(.)ing invisibly.
Examples
norm <- function(x) sqrt(x%*%x)
norm(1:4)
## An anonymous function:
(function(x,y){ z <- x^2 + y^2; x+y+z })(0:7, 1)