as.ffdf: Coercing to ffdf and data.frame

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

Coercing to ffdf and data.frame

Description

Functions for coercing to ffdf and data.frame

Usage

as.ffdf(x, ...)
## S3 method for class 'ff_vector'
as.ffdf(x, ...)
## S3 method for class 'ff_matrix'
as.ffdf(x, ...)
## S3 method for class 'data.frame'
as.ffdf(x, vmode=NULL, col_args = list(), ...)
## S3 method for class 'ffdf'
as.data.frame(x, ...)

Arguments

x	the object to be coerced
vmode	optional specification of the vmodes of columns of the data.frame. Either a character vector of vmodes (named with column names of the data.frame or recycled if not named) or a list named with vmodes where each element identifies those columns of the data.frame that should get the vmode encoded in the name of the element
col_args	further arguments; passed to ff
...	further arguments; passed to ffdf for .ff_vector, .ff_matrix and .data.frame methods, ignored for .ffdf identity method

Value

'as.ffdf' returns an object of class ffdf, 'as.data.frame' returns an object of class data.frame

Author(s)

Jens Oehlschlägel

See Also

is.ffdf, ffdf, data.frame

Examples

  d <- data.frame(x=1:26, y=letters, z=Sys.time()+1:26, stringsAsFactors = TRUE)
  ffd <- as.ffdf(d)
  stopifnot(identical(d, as.data.frame(ffd)))
  rm(ffd); gc()

ff documentation built on Feb. 16, 2023, 7:48 p.m.