ffdfsort: Sorting: convenience wrappers for data.frames

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

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

See Also

sort, ramsort or ffsort
order, ramorder or fforder

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 documentation built on April 4, 2025, 6:05 a.m.