Count number of random effect levels in a mixed model

Returns the number of group levels of random effects from mixed models.

Usage

n_grouplevels(x, ...)

Arguments

x

A mixed model.

...

Additional arguments that can be passed to the function. Currently, you can use data to provide the model data, if available, to avoid retrieving model data multiple times.

Value

The number of group levels in the model.

Examples

data(sleepstudy, package = "lme4")
set.seed(12345)
sleepstudy$grp <- sample(1:5, size = 180, replace = TRUE)
sleepstudy$subgrp <- NA
for (i in 1:5) {
  filter_group <- sleepstudy$grp == i
  sleepstudy$subgrp[filter_group] <-
    sample(1:30, size = sum(filter_group), replace = TRUE)
}
model <- lme4::lmer(
  Reaction ~ Days + (1 | grp / subgrp) + (1 | Subject),
  data = sleepstudy
)
n_grouplevels(model)
#> Group      | N_levels
#> ---------------------
#> subgrp     |       30
#> grp        |        5
#> Subject    |       18
#> subgrp:grp |      108