data_process.1_core: Data Process
In polypharmacy: Calculate Several Polypharmacy Indicators

data_process but with only 1 core. To use in the multicores process.

data_process.1_core(
  Rx_deliv,
  Rx_id,
  Rx_drug_code,
  Rx_drug_deliv,
  Rx_deliv_dur,
  Cohort = NULL,
  Cohort_id = NULL,
  Hosp_stays = NULL,
  Hosp_id = NULL,
  Hosp_admis = NULL,
  Hosp_discharge = NULL,
  study_start = NULL,
  study_end = NULL,
  grace_fctr = 0.5,
  grace_cst = 0,
  max_reserve = NULL
)

`Rx_deliv`	Name of the table listing all prescription drugs deliveries including the run-in period. See Details.
`Rx_id`	Column name of `Rx_deliv` containing individual unique identifier (any format).
`Rx_drug_code`	Column name of `Rx_deliv` that contains the drug unique identifier (any format).
`Rx_drug_deliv`	Column name of `Rx_deliv` that contains the dates of the drug delivery (Date format, see Details).
`Rx_deliv_dur`	Column name of `Rx_deliv` that contains the duration of the delivery (integer number).
`Cohort`	Name of the table providing the unique identifiers of the study cohort. Only the ids listed in both the `Cohort` and the `Rx_deliv` tables will be returned. if `Cohort = NULL`, all ids of the `Rx_deliv` table will be returned.
`Cohort_id`	Column name of `Cohort` containing individual’s unique identifiers (same format as `Rx_id`). If `Cohort` is not `NULL` and `Cohort_id` is `NULL`, `Cohort_id` will take the same value as `Rx_id`.
`Hosp_stays`	Name of the table listing all hospital stays. (see Details for possible format).
`Hosp_id`	Column name of `Hosp_stays` containing individual’s unique identifier (same format as `Rx_id`). If `Hosp_stays` is not `NULL` and `Hosp_id` is `NULL`, `Hosp_id` will take the same value as `Rx_id`.
`Hosp_admis`	Column name of `Hosp_stays` that contains the date of admission in hospital (Date format, see Details).
`Hosp_discharge`	Column name of Hosp_stays that contains the date of discharge from hospital (Date format, see Details).
`study_start`	Defines the first and last day of the study period for which the polypharmacy indicator(s) need to be calculated. All treatment periods prior to `study_start` and past `study_end` are not transcribed into the result table (Date format, see Details).
`study_end`	Defines the first and last day of the study period for which the polypharmacy indicator(s) need to be calculated. All treatment periods prior to `study_start` and past `study_end` are not transcribed into the result table (Date format, see Details).
`grace_fctr`	Numbers ≥ 0. Two types of grace periods can be applied. One is proportional to the treatment duration of the latest delivery (`grace_fctr`) and the other is a constant number of days (`grace_cst`).
`grace_cst`	Numbers ≥ 0. Two types of grace periods can be applied. One is proportional to the treatment duration of the latest delivery (`grace_fctr`) and the other is a constant number of days (`grace_cst`).
`max_reserve`	An integer number ≥ 0 or `NULL`. Longest treatment duration, in days, that can be stored from successive overlapping deliveries. When `max_reserve = NULL` no limit is applied. When `max_reserve = 0` no accumulation of extra treatment duration is accounted for.

data.table with four (4) variables:

The individual unique identifier which name is defined by Rx_id.
The drug unique identifier which name is defined by Rx_drug_code.
tx_start: The date of initiation of the reconstructed continued treatment (format as date).
tx_end: The date of the last day of the reconstructed continued treatment (format as date).