if_date {healthdb}

Interpret if any n elements drawn from a date vector could be some days apart within some time span

Description

Given a vector of dates x, interpret if there could be at least one set of n elements taken from x satisfy that adjacent elements in the set are at least certain days apart AND the dates in the set are within the specified time span. When identifying events/diseases from administrative data, definitions often require, e.g., n diagnoses that are at least some days apart within some years. This function is intended for such use and optimized to avoid looping through all n-size combinations in x. This function does not work with remote table input.

Usage

if_date(
  x,
  n,
  apart = NULL,
  within = NULL,
  detail = FALSE,
  align = c("left", "right"),
  dup.rm = TRUE,
  ...
)

Arguments

x

A character or Date vector

n

An integer for the size of a draw

apart

An integer specifying the minimum gap (in days) between adjacent dates in a draw.

within

An integer specifying the maximum time span (in days) of a draw.

detail

Logical for whether return result per element of x.The default is FALSE, which returns one logical summarized by any(). Detail is not available if apart was supplied without within because sets that satisfied the condition could overlap, and records within a set may be far apart; thus, no unambiguous way to label by element.

align

Character, define if the time span for each record should start ("left") or end ("right") at its current date. Defaults to "left". See 'flag_at' argument in restrict_date() for detail.

dup.rm

Logical for whether multiple records on the same date should be count as one in calculation. Only applicable when within is supplied without apart; duplicated dates have no impact when apart is present as the n dates must be distinct if they were apart. Default is TRUE.

...

Additional argument passing to data.table::as.IDate() for date conversion.

Value

Single or a vector of logical for whether there is any draw from x satisfied the conditions

See Also

restrict_date()

Examples

dates_of_records <- sample(seq(as.Date("2015-01-01"), as.Date("2021-12-31"), 7), 10)

# whether there is any 3 records at least 30 days apart within 2 years
if_date(dates_of_records, n = 3, apart = 30, within = 365 * 2)

# specified either apart or within or both
if_date(dates_of_records, n = 2, within = 365)