splitFromTo: splitFromTo

In tagteam/heaven: Data Preparation Routines for Medical Registry Data

splitFromTo

Description

splitFromTo is devised to split a series of records in multiple records based on entry/exit dates provided from another splitting guide dataset. At start each record has variables representing stand and end of time - after the split time of a split record end at the time of a split one one record and represent the start of time on the next record.

The function is useful for analysis of data where temporary events occur. These may be drugs treatment, pregnancy etc. For a situation of pregnancy for example it may be useful for analysis to split a person into three records representing time before, during and after pregnancy.

The input is first "base data" id/in/out (and other variables) that may already have been split by other functions. The other data is a sequence of id/from/to/value/name - that may represent multiple conditions with from/to and with "name" to distinguish.

Usage

splitFromTo(indat,splitdat,invars,splitvars,default="0",datacheck=TRUE)

Arguments

indat	- base data with id, start, end and other data - possibly already split
splitdat	- Data with splitting guide - id/from/to/value/name
invars	- vector of column names for id/entry/exit - in that order, example: c("id","start","end")
splitvars	- vector of column names containing dates to split by. example: c("id","start","end","value","name") - must be in that order!
default	- Value given to intervals not given a value by the function.
datacheck	- This function can crash or produce incorrect results if input data have overlapping intervals or negative intervals in any of the two input datasets. Thic is checked and error produced by datacheck. Can be omitted if data are checked otherwise

Details

The input to this function are two data.tables and two lists of the critical variables. The BASE data it the data to be split. This data must have a variable to identify participants and start/end times.

The other table (SPLITTINGUIDE) contains possibly multiple records for each participants with id/from/to/value/name.

The program checks that intervals are not negative and that intervals for each "name" and each individual do not overlap. Violation stops the program with error. Overlaps may occur in real situations, but the user needs to make decisions regarding this prior to this function.

It is required that the splittingguide contains at least one record. Missing data for key variables are not allowed and will cause errors.

This function is identical to the lexisFromTo function with the change that "events" are not considered.

Value

The function returns a new data table where records have been split according to the splitting guide dataset. Variables unrelated to the splitting are left unchanged.

Author(s)

Christian Torp-Pedersen

See Also

splitFromTo

Examples

library(data.table)
dat <- data.table(id=c("A","A","B","B","C","D"),
                 start=as.Date(c(0,100,0,100,200,400),origin='1970-01-01'),
                 end=as.Date(c(100,200,100,200,300,500),origin='1970-01-01'))
split <- data.table (id=c("A","A","A","A","B","B","B","D","D"),
                    start=as.Date(c(0,50,25,150,110,150,400,300,500),origin='1970-01-01'),
                    end= as.Date(c(25,75,150,151,120,250,500,400,500),origin='1970-01-01'),
                    value=c(1,2,3,4,1,2,3,6,7),
                    name=c("d1","d1","d2","d2","d1","d1","d2","d3","d4"))
#Show the dataset:
dat[]
split[]                   
temp <- splitFromTo(dat # inddato with id/in/out/event
                   ,split # Data with id and dates
                   ,c("id","start","end") #names of id/in/out/event - in that order
                  ,c("id","start","end","value","name")) #Nmes var date-vars to split by

tagteam/heaven documentation built on April 26, 2024, 6:22 a.m.