Parentheses and Braces

Description

Open parenthesis, (, and open brace, {, are .Primitive functions in R.

Effectively, ( is semantically equivalent to the identity function(x) x, whereas { is slightly more interesting, see examples.

Usage

( ... )

{ ... }

Value

For (, the result of evaluating the argument. This has visibility set, so will auto-print if used at top-level.

For {, the result of the last expression evaluated. This has the visibility of the last evaluation.

References

Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) The New S Language. Wadsworth & Brooks/Cole.

See Also

if, return, etc for other objects used in the R language itself.

Syntax for operator precedence.

Examples

f <- get("(")
e <- expression(3 + 2 * 4)
identical(f(e), e)

do <- get("{")
do(x <- 3, y <- 2*x-3, 6-x-y); x; y

## note the differences
(2+3)
{2+3; 4+5}
(invisible(2+3))
{invisible(2+3)}