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NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
Current content can be found at unidata.ucar.edu.
To learn about what's going on, see About the Archive Site.
Here's a simple example that shows how to create a compound data type, or table:
>>> # open a new file for writing
>>> import netCDF4
>>> ncfile = netCDF4.Dataset('test.h5','w')
>>> # create an unlimited dimension called 'station'
>>> ncfile.createDimension('station',False)
>>> # create a compound datatype.
>>> # (a list of 3-tuples containing
>>> # the name of each member, it's primitive data type, and it's size).
>>> # Only fixed-size primitive data types allowed (no variable length
>>> # strings, or other compound types)
>>> # Members can be multi-dimensional arrays (in which case the third
>>> # element is a shape tuple instead of a scalar).
>>> datatype = [('latitude', 'f4',1), ('longitude', 'f4',1),
>>> ('sfc_press','i4',1), ('temp_sounding','f4',10)]
>>> table = ncfile.createUserType(datatype,'compound','station_data')
>>> # create a variable with this data type.
>>> statdat = ncfile.createVariable('station_obs', table, ('station',))
>>> # write one record of data.
>>> statdat[0] = (40.78,-73.99,1002,
>>> (290.2,282.5,279.,277.9,276.,266.,264.1,260.,255.5,243.))
>>> # close and reopen the file, take a look at the data.
>>> ncfile.close()
>>> ncfile = netCDF4.Dataset('test.h5')
>>> statdat = ncfile.variables['station_obs']
>>> # retrieve the data.
>>> statdatout = statdat[:]
>>> # print the data type
>>> print statdatout.dtype
[('latitude', '>f4'), ('longitude', '>f4'), ('sfc_press', '>i4'),
('temp_sounding', '>f4', (10,))]
>>> # print the data. >>> print statdatout[:][ (40.779998779296875, -73.989997863769531, 1002, array([ 290.20001221, 282.5 , 279. , 277.8999939 ,
276. , 266. , 264.1000061 , 260. ,
255.5 , 243. ], dtype=float32))]
The primary restriction is that you can't yet have nested compound data
types (compound data types whose elements are also compound data types).
The netCDF4_classic module provides a high-degree of compatibility with
the most popular python netCDF3 module, Scientific.IO.NetCDF. It can
read or write NETCDF3 and NETCDF4_CLASSIC files, and can use zlib
compression in NETCDF4_CLASSIC mode.
For more information, and to download the source, see http://code.google.com/p/netcdf4-python/ Regards, -JeffP.S. Russ or Ed, could you update the URL on http://www.unidata.ucar.edu/software/netcdf/software.html to point to the google URL?
-- 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 ============================================================================== To unsubscribe netcdfgroup, visit: http://www.unidata.ucar.edu/mailing-list-delete-form.html ==============================================================================
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