Coercing to ffdf and data.frame

Functions for coercing to ffdf and data.frame

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

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()
#>           used (Mb) gc trigger  (Mb) max used  (Mb)
#> Ncells 1021688 54.6    1994352 106.6  1994352 106.6
#> Vcells 1882674 14.4    8388608  64.0  3877600  29.6