doBy (version 4.6.21)

by-lapply: Formula based version of lapply and sapply

Description

This function is a wrapper for calling lapply on the list resulting from first calling splitBy.

Usage

lapply_by(data, formula, FUN, ...)
lapplyBy(formula, data = parent.frame(), FUN, ...)
sapply_by(data, formula, FUN, ..., simplify = TRUE, USE.NAMES = TRUE)
sapplyBy(
  formula,
  data = parent.frame(),
  FUN,
  ...,
  simplify = TRUE,
  USE.NAMES = TRUE
)

Value

A list.

Arguments

data

A dataframe.

formula

A formula describing how data should be split.

FUN

A function to be applied to each element in the split list, see 'Examples' below.

...

optional arguments to FUN.

simplify

Same as for sapply

USE.NAMES

Same as for sapply

Author

Søren Højsgaard,

See Also

splitBy, split_by

Examples

fun <- function(x) range(x$uptake)
lapplyBy(~Treatment + Type, data=CO2, FUN=fun)
sapplyBy(~Treatment + Type, data=CO2, FUN=fun)

# Same as
lapply(splitBy(~Treatment + Type, data=CO2), FUN=fun)