UniqueVariables: Extracts the unique non-time dependent variables per patient, from an
unbalanced data set
Description
This function extracts a set of unique variables within a
patient, returning a data frame with columns, patient identification and
variables selected. Each row corresponds to the data for each individual.
Usage
UniqueVariables(data, var.col, id.col = "ID")
Value
A data frame with patient identification and covariates selected.
Each row corresponds to the data for each individual. Note that, this can
be only used for non-time dependent covariates. If extracting unique time
dependent covariates, the function gives an error, because it can't select
what is the unique covariate.
Arguments
data
data frame, or matrix, with at least a column of patient
identification and a covariate column.
var.col
vector of column names or column numbers, of the variables
(non-time dependent). Cannot have mix of numbers and column names.
id.col
column name or column number of the patient identification.
Author
Ines Sousa
Details
This function can be used, when longitudinal data is in the
unbalanced format, and it is necessary, for example, to extract the set of
unique baseline covariates, or any non-time dependent variables, that in
the unbalanced format, are repeated for each observation row. Also, if the
original data frame has survival data, this can also be used to extract the
survival information from the original data set.