coef.lmList {nlme} | R Documentation

## Extract lmList Coefficients

### Description

The coefficients of each `lm` object in the `object` list are extracted and organized into a data frame, with rows corresponding to the `lm` components and columns corresponding to the coefficients. Optionally, the returned data frame may be augmented with covariates summarized over the groups associated with the `lm` components.

### Usage

    ## S3 method for class 'lmList'
    coef(object, augFrame, data, which, FUN,
       omitGroupingFactor, ...)

### Arguments

`object` | an object inheriting from class `"lmList"`, representing a list of `lm` objects with a common model.
`augFrame` | an optional logical value. If `TRUE`, the returned data frame is augmented with variables defined in the data frame used to produce `object`; else, if `FALSE`, only the coefficients are returned. Defaults to `FALSE`.
`data` | an optional data frame with the variables to be used for augmenting the returned data frame when `augFrame = TRUE`. Defaults to the data frame used to fit `object`.
`which` | an optional positive integer or character vector specifying which columns of the data frame used to produce `object` should be used in the augmentation of the returned data frame. Defaults to all variables in the data.

`FUN`

an optional summary function or a list of summary functions to be applied to group-varying variables, when collapsing the data by groups. Group-invariant variables are always summarized by the unique value that they assume within that group. If `FUN` is a single function it will be applied to each non-invariant variable by group to produce the summary for that variable. If `FUN` is a list of functions, the names in the list should designate classes of variables in the frame such as `ordered`, `factor`, or `numeric`. The indicated function will be applied to any group-varying variables of that class. The default functions to be used are `mean` for numeric factors, and `Mode` for both `factor` and `ordered`. The `Mode` function, defined internally in `gsummary`, returns the modal or most popular value of the variable. It is different from the `mode` function that returns the S-language mode of the variable.

`omitGroupingFactor` | an optional logical value. When `TRUE` the grouping factor itself will be omitted from the group-wise summary of `data` but the levels of the grouping factor will continue to be used as the row names for the returned data frame. Defaults to `FALSE`.
`...` | some methods for this generic require additional arguments. None are used in this method.

### Value

a data frame inheriting from class `"coef.lmList"` with the estimated coefficients for each `"lm"` component of `object` and, optionally, other covariates summarized over the groups corresponding to the `"lm"` components. The returned object also inherits from classes `"ranef.lmList"` and `"data.frame"`.

### Author(s)

José Pinheiro and Douglas Bates bates@stat.wisc.edu

### References

Pinheiro, J. C. and Bates, D. M. (2000), Mixed-Effects Models in S and S-PLUS, Springer, New York, esp. pp. 457-458.

### See Also

`lmList`, `fixed.effects.lmList`, `ranef.lmList`, `plot.ranef.lmList`, `gsummary`

### Examples

    fm1 <- lmList(distance ~ age|Subject, data = Orthodont)
    coef(fm1)
    coef(fm1, augFrame = TRUE)

[Package nlme version 3.1-131 Index]