save.ffdf saves all ffdf data.frames in the given dir. Each column
is stored as with filename <ffdfname>$<colname>.ff. All variables given in "..." are stored in ".RData" in the same directory.
The data can be reloaded by starting a R session in the directory or by using load.ffdf.
Note that calling save.ffdf multiple times for the same directory
will only store the ffdf's that were given in the last call.
ffdf data.frames, ff vectors, or other variables to be saved in the directory
dir
path where .RData file will be saved and all columns of supplied ffdf's. It will be created if it doesn't exist.
clone
should the ff vectors be clone'd, creating a snapshot of the supplied ffdf or ff objects?
This should only be necessary if you still need the ff vectors in their current storage location.
relativepath
logical if TRUE the stored ff vectors will have relative paths, making moving the data to another storage a simple
copy operation.
overwrite
logical If TRUEsave.ffdf will overwrite
an previous stored ffdf, .Rdata file.
Details
Using save.ffdf automagically sets the finalizers of the ff
vectors to "close". This means that the data will be preserved on disk when the
object is removed or the R sessions is closed. Data can be deleted either using
delete or by removing the directory where the object were saved
(dir).
Note
When saving in the temporary directory pointed at by getOption("fftempdir"), ff assumes that the
resulting files are to be deleted. Be sure to change the finalizers of the
ff vectors when saving in the temporary directory.
See Also
load.ffdf
Examples
iris.ffdf <- as.ffdf(iris)
td <- tempfile()
# save the ffdf into the supplied directory
save.ffdf(iris.ffdf, dir=td)
# what in the directory?
dir(td)
#remove the ffdf from memory
rm("iris.ffdf")
# and reload the stored ffdf
load.ffdf(dir=td)
tf <- paste(tempfile(), ".zip", sep="")
packed <- pack.ffdf(file=tf, iris.ffdf)
#remove the ffdf from memory
rm("iris.ffdf")
# restore the ffdf from the packed ffdf
unpack.ffdf(tf)