Description Usage Arguments Details Value Note Author(s) See Also Examples
Simpe low-level interface for reading and writing vectors from ff files.
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x |
an ff object |
i |
a start position in the ff file |
n |
number of elements to read |
value |
vector of elements to write |
add |
TRUE if the values should rather increment than overwrite at the target positions |
readwrite.ff
combines the effects of read.ff
and write.ff
in a single operation: it retrieves the old values starting from position i
before changing them.
getset.ff
will maintain na.count
.
read.ff
returns a vector of values, write.ff
returns the 'changed' ff object (like all assignment functions do) and readwrite.ff
returns the values at the target position.
More precisely readwrite.ff(x, i, value, add=FALSE)
returns the old values at the position i
while readwrite.ff(x, i, value, add=TRUE)
returns the incremented values of x
.
read.ff
, write.ff
and readwrite.ff
are low level functions that do not support ramclass
and ramattribs
and thus will not give the expected result with factor
and POSIXct
Jens Oehlschlägel
getset.ff
for low-level scalar access and [.ff
for high-level access
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