names {base}R Documentation

The Names Attribute of an Object

Description

Functions to get or set the names of an object.

Usage

names(x)
names(x) <- value

Arguments

x an R object.
value a character vector of up to the same length as x, or NULL.

Details

names is a generic accessor function, and names<- is a generic replacement function. The default methods get and set the "names" attribute of a vector or list.

If value is shorter than x, it is extended by character NAs to the length of x.

It is possible to update just part of the names attribute via the general rules: see the examples. This works because the expression there is evaluated as z <- "names<-"(z, "[<-"(names(z), 3, "c2")).

Value

For names, NULL or a character vector of the same length as x.
For names<-, the updated object. (Note that the value of names(x) <- value is that of the assignment, value, not the return value from the left-hand side.)

References

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

Examples

data(islands)
# print the names attribute of the islands data set
names(islands)

# remove the names attribute
names(islands) <- NULL

z <- list(a=1, b="c", c=1:3)
names(z)
# change just the name of the third element.
names(z)[3] <- "c2"
z

## assign just one name
z <- 1:3
names(z)
# change just the name of the third element.
names(z)[2] <- "b"
z

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