miscset (version 0.3.1)

gapply: Apply a Function by a Grid on a List

Description

gapply applies a function on a data.frame by using named list entries as grid. Support of multicore processing via mclapply. levels is a method to retrieve the grid of a gapply object. as.data.frame is a simplified rbind version which adds the grid to the output.

Usage

gapply(d, by, fun, ..., drop = F, cores = 1)
## S3 method for class 'gapply':
levels(x)
## S3 method for class 'gapply':
as.data.frame(x, ...)
## S3 method for class 'gapply':
as.data.table(x, keyv = NULL, ...)

Arguments

d

A data.frame or data.table object.

by

A character vector with colnames for the grid to subset.

fun

A function to apply on d.

...

Additional arguments to fun or to as.data.frame method.

drop

Drop grid columns for fun.

cores

Number of multicores as mc.cores in mclapply.

x

Object of class gapply.

keyv

Character vector for data.table keys.

Details

The output of gapply is a list inheriting from the S3 class gapply which stores the grid of the original data. Support for subsetting grid entries is not yet supported.

See Also

mclapply, setkeyv

Examples

#

f <- function (x) c(conc.diff = diff(range(x$conc)), uptake.sum=sum(x$uptake))
d <- gapply(CO2, c('Type', 'Treatment'), f)
d
levels(d)
as.data.frame(d)

#