R: Get ramclass and ramattribs

ramattribs {ff} | R Documentation

## Get ramclass and ramattribs

### Description

Functions `ramclass` and `ramattribs` return the respective virtual attributes, that determine which class (and attributes) an ff object receives when subscripted (or coerced) to ram.

### Usage

    ramclass(x, ...)
    ## S3 method for class 'ff'
    ramclass(x, ...)
    ## Default S3 method:
    ramclass(x, ...)
    ramattribs(x, ...)
    ## S3 method for class 'ff'
    ramattribs(x, ...)
    ## Default S3 method:
    ramattribs(x, ...)

### Arguments

`x` | `x`
`...` | further arguments (not used)

### Details

`ramclass` and `ramattribs` provide a general mechanism to store atomic classes in ff objects, for example `factor` – see `levels.ff` – and `POSIXct`, see the example.

### Value

`ramclass` returns a character vector with classnames and `ramattribs` returns a list with names elemens just like `attributes`. The vectors `ramclass_excludes` and `ramattribs_excludes` name those attributes, which are not exported from ff to ram objects when using `as.ram`.

### Author(s)

Jens Oehlschlägel

### See Also

`ff`, `virtual`, `as.ram`, `levels.ff`, `attributes`, `DateTimeClasses`

### Examples

      x <- ff(as.POSIXct(as.POSIXlt(Sys.time(), "GMT")), length=12)
      x
      ramclass(x)
      ramattribs(x)
      class(x[])
      attributes(x[])
      virtual(x)$ramattribs$tzone = NULL
      attributes(x[])
      rm(x); gc()

[Package ff version 2.2-13 Index]