by-lapply function

Formula based version of lapply and sapply

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

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
)

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

Returns

A list.

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)

See Also

splitBy, split_by

Author(s)

Søren Højsgaard, sorenh@math.aau.dk