Count the number of subjects that a cdm_table has.
Examples
person <- dplyr::tibble(
  person_id = 1, gender_concept_id = 0, year_of_birth = 1990,
  race_concept_id = 0, ethnicity_concept_id = 0
)
observation_period <- dplyr::tibble(
  observation_period_id = 1, person_id = 1,
  observation_period_start_date = as.Date("2000-01-01"),
  observation_period_end_date = as.Date("2023-12-31"),
  period_type_concept_id = 0
)
cdm <- cdmFromTables(
  tables = list("person" = person, "observation_period" = observation_period),
  cdmName = "test"
)
#> Warning: ! 5 casted column in person as do not match expected column type:
#> • `person_id` from numeric to integer
#> • `gender_concept_id` from numeric to integer
#> • `year_of_birth` from numeric to integer
#> • `race_concept_id` from numeric to integer
#> • `ethnicity_concept_id` from numeric to integer
#> Warning: ! 3 casted column in observation_period as do not match expected column type:
#> • `observation_period_id` from numeric to integer
#> • `person_id` from numeric to integer
#> • `period_type_concept_id` from numeric to integer
numberSubjects(cdm$observation_period)
#> [1] 1