expand.nested {coxme} | R Documentation |

## Expand nested factors

### Description

Expand out the data frame for a nested factor such as (1| a/b).
This is used by the variance function routines of `coxme`

.

### Usage

```
expand.nested(x)
```

### Arguments

`x` |
A data frame containing the nesting variables |

### Details

The initialize function of a `coxme`

variance family is
passed, as one of its arguments, a data frame `G`

containing
the grouping variables, each of which is a factor..
Assume a nested factor `(1| a/b)`

in the model formula and
a data set whose first few rows are:

a b 1 1 1 2 2 1

The function will replace the second column with a variable named
`a/b`

and values of 1/1, 1/2, 2/1, etc.

### Value

an updated data frame

### Author(s)

Terry Therneau

### See Also

[Package

*coxme*version 2.2-20 Index]