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Calculate number of subjects by treatment and stratum

Source: R/by_strata_by_trt.R
n_subj.Rd

Calculate the number of subjects by treatment and stratum.

Usage

n_subj(dat, cell_index, subjectid_var, ...)

Arguments

dat

data.table. The analysis data set.

cell_index

A vector of integers referencing the rows of dat (as specified by the INDEX_ column in dat) that match the population to be analyzed. See the "Endpoint Events" vignette in ramnog for more information.

subjectid_var

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

...

Optional parameters.

Value

A data.table containing the number of subjects for the given combination of treatment and stratum.

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(dat, cell_index = dat[["INDEX_"]], subjectid_var = "USUBJID")
#>           description qualifiers  label value
#>                <char>     <char> <char> <num>
#> 1: Number of subjects       <NA>      N     3