Ed Hartnett wrote:
Jeff Whitaker <jswhit@xxxxxxxxxxx> writes:
In netcdf-4.0, I don't see how to create variables which are arrays of
strings with length > 1. I see how to create arrays of
single-characters, and arrays of variable-length strings, but not
strings of a specified length.
Am I missing something, or is this not supported by HDF5?
Strings are variable length by their nature.
How about a two dimensional array of NC_CHAR?
Ed: I use arrays of fixed length strings, padded with spaces, quite a
bit. This simplifies the memory management issues associated with
arrays of variable length strings (which have no counterpart in Fortran
90/95, although they are allowed in Fortran 2003). Below is an excerpt
from my previous reply which explains why I don't like using 2-D arrays
of characters to represent 1-D arrays of fixed-length strings:
Russ: I realize you can use a array of shape ndim,8 to store an array of
ndim 8 character strings. Thats the way I've done it with netcdf-3 - it
just feels clunky. A typical use case for me is station data, where you
want to store the name of the station. I end up the with an array of
characters shaped (nstations,ncars) - in fortran I read it into an
(nstations,nchars) character(len=1) array (after first finding out what
both nstations and nchars are), then reshape it into a (nstations)
character(len=nchars) array. I'd rather just read it into a
character(len=nchars) array straight off. Not a show stopper for sure,
but it would be more convenient. I realize that specifying the data
type would be tricky, instead of NC_CHAR, do you have a bunch of new
types NC_CHAR1, NC_CHAR2, ... NC_CHAR120? Or a new function datatype =
nc_set_chartype(nchars)? However, I bet it would get used a lot more
than the esoteric datatypes you have in netcdf-4 already (enums and
opaque for example).
Jeffrey S. Whitaker Phone : (303)497-6313
Meteorologist FAX : (303)497-6449
NOAA/OAR/PSD R/PSD1 Email : Jeffrey.S.Whitaker@xxxxxxxx
325 Broadway Office : Skaggs Research Cntr 1D-124
Boulder, CO, USA 80303-3328 Web : http://tinyurl.com/5telg
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