The (Storage) Mode of an Object

Description

Get or set the type or storage mode of an object.

Usage

mode(x)
mode(x) <- value
storage.mode(x)
storage.mode(x) <- value

Arguments

Details

Both mode and storage.mode return a character string giving the (storage) mode of the object — often the same — both relying on the output of typeof(x), see the example below.

The two assignment versions are currently identical. Both mode(x) <- "newmode" and storage.mode(x) <- "newmode" change the mode or storage.mode of object x to newmode. This is only supported if there is an appropriate as.newmode function, for example "logical", "integer", "double", "complex", "raw", "character", "list", "expression", "name", "symbol" and "function".

As storage mode "single" is only a pseudo-mode in R, it will not be reported by mode or storage.mode: use attr(object, "Csingle") to examine this. However, the assignment versions can be used to set the mode to "single", which sets the real mode to "double" and the "Csingle" attribute to TRUE. Setting any other mode will remove this attribute.

Note (in the examples below) that some calls have mode "(" which is S compatible.

Mode names

Modes have the same set of names as types (see typeof) except that

• types "integer" and "double" are returned as "numeric".
• types "special" and "builtin" are returned as "function".
• type "symbol" is called mode "name".
• type "language" is returned as "(" or "call".

References

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

See Also

typeof for the R-internal “mode”, attributes.

Examples

sapply(options(),mode)

cex3 <- c("NULL","1","1:1","1i","list(1)","data.frame(x=1)", "pairlist(pi)",
  "c", "lm", "formals(lm)[[1]]",  "formals(lm)[[2]]",
  "y~x","expression((1))[[1]]", "(y~x)[[1]]", "expression(x <- pi)[[1]][[1]]")
lex3 <- sapply(cex3, function(x) eval(parse(text=x)))
mex3 <- t(sapply(lex3, function(x) c(typeof(x), storage.mode(x), mode(x))))
dimnames(mex3) <- list(cex3, c("typeof(.)","storage.mode(.)","mode(.)"))
mex3

## This also makes a local copy of 'pi':
storage.mode(pi) <- "complex"
storage.mode(pi)
rm(pi)