tcctomat {rmutil} | R Documentation |
Create a Time-constant, Inter-individual Covariate (tccov) Object
Description
tcctomat
creates an object of class, tccov
, from a
vector or matrix containing time-constant or inter-individual baseline
covariates or a model formula. It can also combine two such objects.
Such objects can be printed. Methods are available for extracting the
covariates, their names, and the formula: covariates
,
names
, and formula
. The method,
transform
, can transform variables in place or by adding
new variables to the object.
To obtain the indexing to expand time-constant or inter-individual
covariates to the size of a repeated measurements response, use
covind
.
Usage
tcctomat(ccov, names=NULL, units=NULL, oldccov=NULL, dataframe=TRUE,
description=NULL)
Arguments
ccov |
A vector, matrix, or dataframe containing time-constant or
inter-individual baseline covariates with one row per individual, a
model formula using vectors of the same size, or an object of class,
|
units |
Optional character vector specifying units of measurements of covariates. |
names |
The names of the covariates (if the matrix does not have column names). |
oldccov |
An object of class, |
dataframe |
If TRUE and factor variables are present, the covariates are stored as a dataframe; if FALSE, they are expanded to indicator variables. If no factor variables are present, covariates are always stored as a matrix. |
description |
An optional named list of character vectors with names of some or all covariates containing their descriptions. |
Value
Returns an object of class, tccov
, containing one matrix or
dataframe for the covariates (z$ccov
) with one row per
individual and possibly the model formula (z$linear
).
Author(s)
J.K. Lindsey
See Also
DataMethods
, covariates
,
description
, formula
,
lvna
, names
,
restovec
, rmna
,
transform
, tvctomat
,
units
Examples
x1 <- gl(4,1)
print(tcc1 <- tcctomat(~x1))
covariates(tcc1)
covariates(tcc1, name="x12")
tcctomat(x1)
tcctomat(x1, dataframe=FALSE)
x2 <- c(0,0,1,1)
print(tcc2 <- tcctomat(~x2, units="days"))
covariates(tcc2)
print(tcc3 <- tcctomat(~x1+x2))
covariates(tcc3)
covariates(tcc3, names=c("x12","x2"))
formula(tcc3)
names(tcc3)
print(tcc4 <- tcctomat(data.frame(x1,x2), units=c(NA,"days")))
covariates(tcc4)
print(tcc5 <- tcctomat(data.frame(x1,x2), dataframe=FALSE, units=c(NA,"days")))
covariates(tcc5)