Building-block: Number of subjects with at least one event

Building-block: Number of subjects with at least one event

Usage

n_subj_event_(dat, intersect_index, subjectid_var)

Arguments

dat

data.table. The analysis data set.

intersect_index

A vector of intergers referencing the rows of dat that match both (1) the population to be analyzed and (2) the defenition of an event

subjectid_var

character. Name of the subject identifier variable in the data (default is "USUBJID").

Value

an interger value

Examples

dat <- data.table::data.table(USUBJID = c("S1", "S2", "S3"))
dat[, INDEX_ := .I]
#>    USUBJID INDEX_
#>     <char>  <int>
#> 1:      S1      1
#> 2:      S2      2
#> 3:      S3      3
data.table::setkey(dat, INDEX_)
n_subj_event_(dat, intersect_index = c(1L, 2L), subjectid_var = "USUBJID")
#> [1] 2