ff (version 4.0.4)

as.ff: Coercing ram to ff and ff to ram objects

Description

Coercing ram to ff and ff to ram objects while optionally modifying object features.

Usage

as.ff(x, ...)
  as.ram(x, ...)
  # S3 method for default
as.ff(x, filename = NULL, overwrite = FALSE, ...)
  # S3 method for ff
as.ff(x, filename = NULL, overwrite = FALSE, ...)
  # S3 method for default
as.ram(x, ...)
  # S3 method for ff
as.ram(x, ...)

Arguments

x

any object to be coerced

filename

path and filename

overwrite

TRUE to overwrite the old filename

…

…

Value

A ram or ff object.

Details

If as.ff.ff is called on an 'ff' object or as.ram.default is called on a non-ff object AND no changes are required, the input object 'x' is returned unchanged. Otherwise the workhorse clone.ff is called. If no change of features are requested, the filename attached to the object remains unchanged, otherwise a new filename is requested (or can be set by the user).

See Also

as.ff.bit, ff, clone , as.vmode, vmode, as.hi

Examples

# NOT RUN {
   message("create ff")
   myintff <- ff(1:12)
   message("coerce (=clone) integer ff to double ff")
   mydoubleff <- as.ff(myintff, vmode="double")
   message("cache (=clone) integer ff to integer ram AND close original ff")
   myintram <- as.ram(myintff) # filename is retained
   close(myintff)
   message("modify ram cache and write back (=clone) to ff")
   myintram[1] <- -1L
   myintff <- as.ff(myintram, overwrite=TRUE)
   message("coerce (=clone) integer ram to double ram")
   mydoubleram <- as.ram(myintram, vmode="double")
   message("coerce (inplace) integer ram to double ram")
   myintram <- as.ram(myintram, vmode="double")
   message("more classic: coerce (inplace) double ram to integer ram")
   vmode(myintram) <- "integer"
   rm(myintff, myintram, mydoubleff, mydoubleram); gc()
# }