Sampling from a data frame

R doBy

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, [email protected]

See Also

orderBy, summaryBy, transformBy, splitBy,

Examples

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

[Package doBy version 1.9 Index]