ffdf to another ffdfffdf called dat
to an existing ffdf called x. Please note
that the data of x will be coerced to the type of
y if the corresponding column of y has a
higher vmode.ffdfappend(x, dat, recode = TRUE, adjustvmode = TRUE,
...)ffdf object where data will be appended
to. If x==NULL a new ffdf object will be
createdffdf object or data.frame
objectx to a higher vmode to make sure
y is appended without loss of information.as.ffdf, when x==NULLffdf object with same physical storage as x
unless the corresponding column of y has a higher
vmode in which case the data will be cloned to the
higher vmodec.ff