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,
`tccov` . In the first two cases, the variables may be factors; if
`dataframe=FALSE` , these are transformed to indicator variables. |

`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, `tccov` , to which `ccov`
is to be added. |

`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)

[Package

*rmutil* version 1.0

Index]