# sindex

##### Index for evaluation of step functions.

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.

- Keywords
- misc

##### 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`

.

##### Examples

```
# NOT RUN {
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)]
# }
```

*Documentation reproduced from package prodlim, version 2018.04.18, License: GPL (>= 2)*