fileformats returns format names, a format definition list or a table of information about the formats that match the given filter conditions.

registerformat registers a format in the io registry

getformatreader gets the function to read a file

getformatwriter gets the function to write a file

  format = NULL,
  ext = NULL,
  read = NULL,
  write = NULL,
  class = NULL,
  rval = c("names", "info", "all")

  format = NULL,
  ext = format,
  read = NULL,
  write = NULL,
  magic = NULL,
  magiclen = NA_integer_,
  class = NULL

getformatreader(file, class = NULL)

getformatwriter(format = NULL, file = NULL, ext = NULL, class = NULL)



Character vector naming the format


Character vector of file extensions (including periods)

read, write

Functions to read and write this format


The S3 class for the format (character vector e.g. 'neuron')


Character vector choosing what kind of return value fileformats will give.


Function to test whether a file is of this format


Optional integer specifying maximum number of bytes required from file header to determine file's type.


Path to a file


  • fileformats returns a character vector, matrix or list according to the value of rval.

  • getformatreader returns a list. The reader can be accessed with $read and the format can be accessed by $format.

  • getformatwriter returns a list. The writer can be accessed with $write.


if a format argument is passed to fileformats it will be matched with partial string matching and iif a unique match exists that will be returned.

getformatreader starts by reading a set number of bytes from the start off the current file and then checks using file extension and magic functions to see if it can identify the file. Presently formats are in a queue in alphabetical order, dispatching on the first match.

getformatwriter output file

If getformatwriter is passed a file argument, it will be processed based on the registered fileformats information and the ext argument to give a final output path in the $file element of the returned list.

If ext='.someext' getformatwriter will use the specified extension to overwrite the default value returned by fileformats.

If ext=NULL, the default, and file='somefilename.someext' then file will be untouched and ext will be set to 'someext' (overriding the value returned by fileformats).

If file='somefile_without_extension' then the supplied or calculated extension will be appended to file.

If ext=NA then the input file name will not be touched (even if it has no extension at all).

Note that if ext=NULL or ext=NA, then only the specified format or, failing that, the file extension will be used to query the fileformats database for a match.

See write.neuron for code to make this discussion more concrete.

See also


# information about the currently registered file formats fileformats(rval='info')
#> format class ext read write magic #> 1 amiralandmarks landmarks .landmarkAscii TRUE TRUE TRUE #> 2 amiralandmarks landmarks .landmarkBin TRUE TRUE TRUE #> 3 amiralandmarks landmarks .am TRUE TRUE TRUE #> 4 amiralandmarks landmarks .amiramesh TRUE TRUE TRUE #> 5 amiramesh im3d .am TRUE TRUE TRUE #> 6 amiramesh im3d .amiramesh TRUE TRUE TRUE #> 7 cmtklandmarks landmarks .landmarks TRUE TRUE TRUE #> 8 fijilandmarks landmarks .points TRUE TRUE TRUE #> 9 fijitraces neuron .traces TRUE FALSE TRUE #> 10 fijitraces neuron .xml TRUE FALSE TRUE #> 11 hxlineset neuron .am TRUE TRUE TRUE #> 12 hxskel neuron .am TRUE TRUE TRUE #> 13 hxsurf hxsurf .surf TRUE TRUE TRUE #> 14 hxsurf hxsurf .am TRUE TRUE TRUE #> 15 hxsurf hxsurf .amiramesh TRUE TRUE TRUE #> 16 neuroml neuron .xml TRUE FALSE TRUE #> 17 neuroml neuron .nml TRUE FALSE TRUE #> 18 neuron.obj neuron .obj TRUE TRUE FALSE #> 19 neuron.ply neuron .ply TRUE TRUE TRUE #> 20 nrrd im3d .nrrd TRUE TRUE TRUE #> 21 nrrd im3d .nhdr TRUE TRUE TRUE #> 22 qs neuron .qs TRUE TRUE FALSE #> 23 rds neuron .rds TRUE TRUE FALSE #> 24 rdsb neuron .rdsb TRUE TRUE FALSE #> 25 swc neuron .swc TRUE TRUE FALSE #> 26 swcng ngraph .swc TRUE FALSE FALSE #> 27 vaa3draw im3d .v3d TRUE FALSE TRUE #> 28 vaa3draw im3d .v3draw TRUE FALSE TRUE #> 29 vtk neuron .vtk FALSE TRUE FALSE
if (FALSE) { registerformat("swc",read=read.swc,write=read.swc,magic=is.swc,magiclen=10, class='neuron') } swc=tempfile(fileext = '.swc') write.neuron(Cell07PNs[[1]], swc) stopifnot(isTRUE(getformatreader(swc)$format=='swc')) unlink(swc)