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CFUN

Collapsing functions for batch processing

Description

These are used in aggregating the chunks resulting from batch processing. They are usually called via do.call

Usage

ccbind(...)
crbind(...)
cfun(..., FUN, FUNARGS = list())
cquantile(..., probs = seq(0, 1, 0.25), na.rm = FALSE, names = TRUE, type = 7)
csummary(..., na.rm = "ignored")
cmedian(..., na.rm = FALSE)
clength(..., na.rm = FALSE)
csum(..., na.rm = FALSE)
cmean(..., na.rm = FALSE)

Arguments

`...`	`...`
`FUN`	a aggregating function
`FUNARGS`	further arguments to the aggregating function
`na.rm`	TRUE to remove NAs
`probs`	see `quantile`
`names`	see `quantile`
`type`	see `quantile`

Details

CFUN	FUN	comment
`ccbind`	`cbind`	like `cbind` but respecting names
`crbind`	`rbind`	like `rbind` but respecting names
`cfun`		`crbind` the input chunks and then apply 'FUN' to each column
`cquantile`	`quantile`	`crbind` the input chunks and then apply 'quantile' to each column
`csummary`	`summary`	`crbind` the input chunks and then apply 'summary' to each column
`cmedian`	`median`	`crbind` the input chunks and then apply 'median' to each column
`clength`	`length`	`crbind` the input chunks and then determine the number of values in each column
`csum`	`sum`	`crbind` the input chunks and then determine the sum values in each column
`cmean`	`mean`	`crbind` the input chunks and then determine the (unweighted) mean in each column

In order to use CFUNs on the result of lapply or ffapply use do.call.

Value

depends on the CFUN used

ff options

xx TODO: extend this for weighted means, weighted median etc.,
google "Re: [R] Weighted median"

Note

Currently - for command line convenience - we map the elements of a single list argument to ..., but this may change in the future.

Author(s)

Jens Oehlschlägel

Examples

X <- lapply(split(rnorm(1000), 1:10), summary)
   do.call("crbind", X)
   do.call("csummary", X)
   do.call("cmean", X)
   do.call("cfun", c(X, list(FUN=mean, FUNARGS=list(na.rm=TRUE))))
   rm(X)

ff

Memory-Efficient Storage of Large Data on Disk and Fast Access Functions

v4.0.4

GPL-2 | GPL-3 | file LICENSE

Authors

Daniel Adler [aut], Christian Gläser [aut], Oleg Nenadic [aut], Jens Oehlschlägel [aut, cre], Martijn Schuemie [aut], Walter Zucchini [aut]

Initial release

2020-10-13