R: Conversion between bit and ff boolean

as.ff.bit {ff} | R Documentation

## Conversion between bit and ff boolean

### Description

Function `as.ff.bit` converts a `bit` vector to a boolean `ff` vector. Function `as.bit.ff` converts a boolean `ff` vector to a `ff` vector.

### Usage

    ## S3 method for class 'bit'
    as.ff(x, filename = NULL, overwrite = FALSE, ...)
    ## S3 method for class 'ff'
    as.bit(x, ...)

### Arguments

`x` | the source of conversion
`filename` | optionally a desired filename
`overwrite` | logical indicating whether we allow overwriting the target file
`...` | further arguments passed to ff in case `as.ff.bit`, ignored in case of `as.bit.ff`

### Details

The data are copied bot bit-wise but integerwise, therefore these conversions are very fast. `as.bit.ff` will attach the ff filename to the bit vector, and `as.ff.bit` will - if attached - use THIS filename and SILENTLY overwrite this file.

### Value

A vector of the converted type

### Note

NAs are mapped to TRUE in 'bit' and to FALSE in 'ff' booleans. Might be aligned in a future release. Don't use bit if you have NAs - or map NAs explicitely.

### Author(s)

Jens Oehlschlägel

### See Also

`bit`, `ff`, `as.ff`, `as.hi.bit`

### Examples

      l <- as.boolean(sample(c(FALSE,TRUE), 1000, TRUE))

      b <- as.bit(l)
      stopifnot(identical(l,b[]))
      b
      f <- as.ff(b)
      stopifnot(identical(l,f[]))
      f
      b2 <- as.bit(f)
      stopifnot(identical(l,b2[]))
      b2
      f2 <- as.ff(b2)
      stopifnot(identical(filename(f),filename(f2)))
      stopifnot(identical(l,f2[]))
      f
      rm(f,f2); gc()

[Package ff version 2.2-13 Index]