R: Merge a Lexis object with a data frame

merge.Lexis {Epi} | R Documentation

## Merge a Lexis object with a data frame

### Description

Merge additional variables from a data frame into a Lexis object.

### Usage

    ## S3 method for class 'Lexis'
    merge(x, y, id, by, ...)

### Arguments

`x` | an object of class `Lexis`
`y` | a data frame
`id` | the name of the variable in `y` to use for matching against the variable `lex.id` in `x`.
`by` | if matching is not done by id, a vector of variable names common to both `x` and `y`
`...` | optional arguments to be passed to `merge.data.frame`

### Details

A `Lexis` object can be considered as an augmented data frame in which some variables are time-dependent variables representing follow-up. The `Lexis` function produces a minimal object containing only these time-dependent variables. Additional variables may be added to a `Lexis` object using the `merge` method.

### Value

A `Lexis` object with additional columns taken from the merged data frame.

### Note

The variable given as the `by.y` argument must not contain any duplicate values in the data frame `y`.

### Author(s)

Martyn Plummer

### See Also

`merge.data.frame`, `subset.Lexis`

[Package Epi version 2.47 Index]