R: Sampling from a data frame

by-sample {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 dataframe.

Examples

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

[Package doBy version 4.6-2 Index]