Test if a file is an SWC format neuron
is.swc(f, TrustSuffix = TRUE)
Path to one or more files
Whether to trust that a file ending in .nrrd or .nhdr is a NRRD
Note that this test is somewhat expensive compared with the other file tests since SWC files do not have a consistent magic value. It therefore often has to read and parse the first few lines of the file in order to determine whether they are consistent with the SWC format.