Appends (ff) vector y to ff vector x.
Please note that the data of x will be coerced to the type of y if y has a higher vmode.
ffappend(x, y, adjustvmode = TRUE, ...)ff object where data will be appended to. If x==NULL a new ff object will be created
ff object or vector object
logical, indicating to coerce x to a higher vmode to make sure y is appended without loss of information.
parameter that will be passed on to chunk interally
ff object with same physical storage as x unless y has a higher vmode in which case the data will be cloned to the higher vmode