Getting and setting dimnames

For ff_arrays you can set dimnames.

# S3 method for class 'ff_array'
dimnames(x)
  # S3 method for class 'ff_array'
dimnames(x) <- value

Arguments

x

a ff array (or matrix)

value

a list with length(dim(x)) elements (either NULL of character vector of length of dimension

Details

if vw is set, dimnames.ff_array returns the appropriate part of the names, but you can't set dimnames while vw is set. dimnames returns NULL for ff_vectors and setting dimnames for ff_vector is not allowed, but setting names is.

Value

dimnames returns a list, see dimnames

Author

Jens Oehlschlägel

See also

dimnames, dim.ff , names.ff , vw, virtual

Examples

  x <- ff(1:12, dim=c(3,4), dimnames=list(letters[1:3], LETTERS[1:4]))
  dimnames(x)
#> [[1]]
#> [1] "a" "b" "c"
#> 
#> [[2]]
#> [1] "A" "B" "C" "D"
#> 
  dimnames(x) <- list(LETTERS[1:3], letters[1:4])
  dimnames(x)
#> [[1]]
#> [1] "A" "B" "C"
#> 
#> [[2]]
#> [1] "a" "b" "c" "d"
#> 
  dimnames(x) <- NULL
  dimnames(x)
#> NULL
  rm(x); gc()
#>           used (Mb) gc trigger  (Mb) max used  (Mb)
#> Ncells 1136595 60.8    1994352 106.6  1994352 106.6
#> Vcells 2107384 16.1    8388608  64.0  3981144  30.4