R: Dimnames of an xts Object

dimnames.xts {xts} | R Documentation

## Dimnames of an xts Object

### Description

Get or set dimnames of an xts object.

### Usage

    ## S3 method for class 'xts'
    dimnames(x)

    ## S3 replacement method for class 'xts'
    dimnames(x) <- value

### Arguments

`x` | an xts object
`value` | a list object of length two. See Details.

### Details

The functions `dimnames.xts` and `dimnames<-.xts` are methods for the base functions `dimnames` and `dimnames<-`.

`xts` objects by design are intended for lightweight management of time-indexed data.

Rownames are redundant in this design, as well as quite burdensome with respect to memory consumption and internal copying costs.

`rownames` and `colnames` in R make use of `dimnames` method dispatch internally, and thus require only modifications to dimnames to enforce the `xts` no rownames requirement.

To prevent accidental setting of rownames, `dimnames<-` for `xts` will simply set the rownames to `NULL` when invoked, regardless of attempts to set otherwise.

This is done for internal compatibility reasons, as well as to provide consistency in performance regardless of object use.

User level interaction with either dimnames or rownames will produce a character vector of the index, formatted based on the current specification of `indexFormat`. This occurs within the call by converting the results of calling `index(x)` to a character string, which itself first creates the object type specified internally from the underlying numeric time representation.

### Value

A list or character string containing coerced row names and/or actual column names.

Attempts to set rownames on xts objects via rownames or dimnames will silently fail. This is your warning.

### Note

All `xts` objects have dimension. There are no `xts` objects representable as named or unnamed vectors.

### Author(s)

Jeffrey A. Ryan

### See Also

`xts`

### Examples

    x <- xts(1:10, Sys.Date()+1:10)
    dimnames(x)
    rownames(x)
    rownames(x) <- 1:10
    rownames(x)
    str(x)

[Package xts version 0.12.1 Index]