requireIsFirstEntry {CohortConstructor}

Restrict cohort to first entry

Description

requireIsFirstEntry() filters cohort records, keeping only the first cohort entry per person.

Usage

requireIsFirstEntry(
  cohort,
  cohortId = NULL,
  indexDate = "cohort_start_date",
  name = tableName(cohort)
)

Arguments

cohort

A cohort table in a cdm reference.

cohortId

IDs of the cohorts to modify. If NULL, all cohorts will be used; otherwise, only the specified cohorts will be modified, and the rest will remain unchanged.

indexDate

Column name in cohort that contains the date to restrict on.

name

Name of the new cohort with the restriction.

Value

A cohort table in a cdm reference.

Examples

library(CohortConstructor)
cdm <- mockCohortConstructor()
cdm$cohort1 <- requireIsFirstEntry(cdm$cohort1)