ff: as.ff.bit – R documentation

Become an expert in R — Interactive courses, Cheat Sheets, certificates and more!

as.ff.bit

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

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

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

v4.0.4

GPL-2 | GPL-3 | file LICENSE

Authors

Daniel Adler [aut], Christian Gläser [aut], Oleg Nenadic [aut], Jens Oehlschlägel [aut, cre], Martijn Schuemie [aut], Walter Zucchini [aut]

Initial release

2020-10-13