sindex {prodlim} | R Documentation |
Index for evaluation of step functions.
Description
Returns an index of positions. Intended for evaluating a step function at selected times. The function counts how many elements of a vector, e.g. the jump times of the step function, are smaller or equal to the elements in a second vector, e.g. the times where the step function should be evaluated.
Usage
sindex(jump.times, eval.times, comp = "smaller", strict = FALSE)
Arguments
jump.times |
Numeric vector: e.g. the unique jump times of a step function. |
eval.times |
Numeric vector: e.g. the times where the step function should be evaluated |
comp |
If "greater" count the number of jump times that are greater (greater or equal when strict==FALSE) than the eval times |
strict |
If TRUE make the comparison of jump times and eval times strict |
Details
If all jump.times
are greater than a particular eval.time
the
sindex returns 0
. This must be considered when sindex is used for
subsetting, see the Examples below.
Value
Index of the same length as eval.times
containing the numbers
of the jump.times
that are smaller than or equal to
eval.times
.
Author(s)
Thomas A. Gerds tag@biostat.ku.dk
Examples
test <- list(time = c(1, 1,5,5,2,7,9),
status = c(1,0,1,0,1,1,0))
fit <- prodlim(Hist(time,status)~1,data=test)
jtimes <- fit$time
etimes <- c(0,.5,2,8,10)
fit$surv
c(1,fit$surv)[1+sindex(jtimes,etimes)]