ff: ffdfsort – R documentation

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ffdfsort

Sorting: convenience wrappers for data.frames

Description

These functions allow convenient sorting and ordering of collections of (ff) vectors organized in (ffdf) data.frames

Usage

dforder(x, ...)
dfsort(x, ...)
ramdforder(x, ...)
ramdfsort(x, ...)
ffdforder(x, ...)
ffdfsort(x, ...)

Arguments

`x`	a `data.frame` (for `dforder, dfsort, ramorder, ramsort`) or an `ffdf` object (for `ffdforder, ffdfsort`)
`...`	further arguments passed to `sort`, `ramsort` or `ffsort` (for objects with one column) or passed to `order`, `ramorder` or `fforder` (for objects with mulitple columns)

Value

the order functions return an (ff) vector of integer order positions, the sort functions return a sorted clone of the (ffdf) input data.frame

Author(s)

Jens Oehlschlägel

Examples

x <- ff(sample(1e5, 1e6, TRUE))
   y <- ff(sample(1e5, 1e6, TRUE))
   z <- ff(sample(1e5, 1e6, TRUE))
   d <- ffdf(x, y, z)
   d2 <- ffdfsort(d)
   d2
   d
   d2 <- d[1:2]
   i <- ffdforder(d2)
   d[i,]
   rm(x, y, z, i, d, d2)
   gc()

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