as.ff.bit: Conversion between bit and ff boolean

In ff: Memory-Efficient Storage of Large Data on Disk and Fast Access Functions

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()

ff documentation built on Sept. 30, 2024, 9:38 a.m.