interpprev {lgtdl} | R Documentation |
These functions provide an interpolation mechanism for objects of
class lgtdl
. The AsIs
method is the vectorized version.
interpprev(x, ...) interpprev.lgtdl(x, time, cov, ...) interpprev.AsIs(x, ...)
x |
x is either an object of class lgtdl or of
class AsIs . It is the object on which interpolation is to be
performed. |
time |
A vector of times at which interpolation is requested. |
cov |
The name of the covariate on which interpolation is
requested. It is only required if x has more than one
covariate. |
... |
Ignored. |
If objects of class lgtdl
are inserted into a data frame they
become a vector with class AsIs
. In order to operate on these
we provide a method for that class. The method is simply a vectorized
version.
interpprev.lgtdl
returns a numeric vector of the interpolated
values of the covariate at the time(s) specified by time
.
interpprev.AsIs
returns a vector of interpolated values of the
covariate. In this case the vector contains one value for each element
x
. time
must be either the same length as x
or
of length one. In the latter case all interpolations are done at that
time.
Robert Gentleman
x1<-data.frame(time=c(1,3,5), cov=c(4,6,8)) x2<-data.frame(time=c(11,13,15), interest=c(66,45,88)) x1<-as.lgtdl(x1) x2<-as.lgtdl(x2) interpprev(x1, c(2,4)) interpprev(x2, c(12, 14))