Identify exogenous (parentless) variables in a DAG.
Usage
query_exogenous(.tdy_dag)
Arguments
- .tdy_dag
A tidy DAG object.
Value
A tibble with columns:
Examples
library(ggdag)
dag <- dagify(
y ~ x + z,
x ~ w
)
query_exogenous(dag)
#> # A tibble: 2 × 2
#> node n_descendants
#> <chr> <int>
#> 1 w 2
#> 2 z 1