R: Sampling from a data frame

sampleBy {doBy} | R Documentation

## Sampling from a data frame

### Description

A data frame is split according to some variables in a formula, and a sample of a certain fraction of each is drawn.

### Usage

    sampleBy(formula, frac = 0.1, replace=FALSE, data = parent.frame(),systematic=FALSE)

### Arguments

`formula` | A formula defining the grouping of the data frame
`frac` | The part of data to be sampled.
`replace` | Is the sampling with replacement
`data` | A data frame
`systematic` | Should sampling be systematic.

### Details

If systematic=FALSE (default) then frac gives the fraction of data sampled. If systematic=TRUE and frac=.2 then every 1/.2 i.e. every 5th observation is taken out.

### Value

A data frame

### Author(s)

Søren Højsgaard, sorenh@math.aau.dk

### See Also

`orderBy`, `summaryBy`, `transformBy`, `splitBy`,

### Examples

    data(dietox)
    sampleBy(formula = ~Evit+Cu, frac=.1, data = dietox)

[Package doBy version 4.5-15 Index]