R: Test if object is opened

is.open {ff} | R Documentation

## Test if object is opened

### Description

Test whether an ff or ffdf object or a `ff_pointer` is opened.

### Usage

    is.open(x, ...)
    ## S3 method for class 'ff'
    is.open(x, ...)
    ## S3 method for class 'ffdf'
    is.open(x, ...)
    ## S3 method for class 'ff_pointer'
    is.open(x, ...)

### Arguments

`x` | an `ff` or `ffdf` object
`...` | further arguments (not used)

### Details

ff objects open automatically if accessed while closed. For ffdf objects we test all of their `physical` components including their `row.names` if they are `is.ff`

### Value

TRUE or FALSE (or NA if not all components of an ffdf object are opened or closed)

### Author(s)

Jens Oehlschlägel

### See Also

`is.readonly`, `open.ff`, `close.ff`

### Examples

      x <- ff(1:12)
      is.open(x)
      close(x)
      is.open(x)
      rm(x); gc()

[Package ff version 2.2-13 Index]