R: A template function for creating groupwise functions

createFunBy {doBy} | R Documentation

## A template function for creating groupwise functions

### Description

A template function for creating groupwise functions

### Usage

    formulaFunBy(formula, group, data, FUN, class = NULL, ...)
    xyFunBy(xy, group, data, FUN, class = NULL, ...)

### Arguments

`formula` | A formula of the form `y ~ x` (which must be variable names in `data`).
`xy` | A character vector with one or two elements (which must be variable names in `data`).
`group` | A right hand sided formula or a character vector defining the grouping of data
`data` | A data frame
`FUN` | The function to be applied
`class` | The class to give the result of the returned value of the created function.
`...` | Further arguments passed on to `FUN`

### Value

A function

### Note

This function is a recent addition and has not been thoroughly tested. Please report bugs.

### Author(s)

Søren Højsgaard, sorenh@math.aau.dk

### See Also

`parseGroupFormula`

### Examples

    ## Example: Create a function for creating groupwise t-tests

    mydata <- data.frame(y=rnorm(32), x=rnorm(32),
    g1=factor(rep(c(1,2),each=16)), g2=factor(rep(c(1,2), each=8)),
    g3=factor(rep(c(1,2),each=4)))

    t.testBy1 <- function(formula, group, data, ...){
      formulaFunBy(formula, group, data, FUN=t.test, class="t.testBy1", ...)
    }

    t.testBy2 <- function(formula, group, data, ...){
      xyFunBy(formula, group, data, FUN=t.test, class="t.testBy1", ...)
    }

    t.testBy1(y~g1, ~g2+g3, data=mydata)
    t.testBy2(y~x, ~g2+g3, data=mydata)

[Package doBy version 4.5-15 Index]