[SciPy-User] Can create, but not access, netCDF variables with no dimension

[Mannucci, Anthony J (335G)]

I am trying to read a netcdf file that has variables created without dimension (they are scalars). Since the file is obtained externally, and written without python, I cannot modify the file. So, the variable I am trying to access is not accessible using scipy.io.netcdf. (I can see the variable with ncdump).

I cannot fully reproduce the problem here, although I can reproduce something similar. Here is some code for discussion:
---
import scipy.io.netcdf as CDF
f = CDF.netcdf_file('simple.nc', 'w')
f.createDimension('time', 10)
time = f.createVariable('time', 'i', ('time',))
time[:] = np.arange(10)
nodimvar = f.createVariable('nodimvar','f8',()) # Guessing this creates a scalar variable.
nodimvar = 8.0 # nodimvar[:] fails with an error. Scalar not indexable.
f.close()

f = CDF.netcdf_file('simple.nc', 'r')
print f.variables.keys()
print f.variables['time'][:]
print f.variables['nodimvar'] # Does not print variable value, just the object.
print f.variables['nodimvar'][:] # Error, scalar is not indexable.
f.close()
-----
The variable name shows up in f.variables.keys(). However, I do not know how to access the variable. Appending [:] to gives an error "IndexError: 0-d arrays can't be indexed.".

In the file I was provided, not included here because it's very large, the variable with no dimensions does not even show with up in keys().

I note that the package netCDF4 seems to handle this case correctly. Even zero-dimension variables are accessed via [:]. No error is generated and the value of the scalar is returned.

Thanks!

-Tony

--
Tony Mannucci
Supervisor, Ionospheric and Atmospheric Remote Sensing Group
 Mail-Stop 138-308,                     Tel > (818) 354-1699
 Jet Propulsion Laboratory,              Fax > (818) 393-5115
 California Institute of Technology,     Email > Tony.Mannucci at jpl.nasa.gov
 4800 Oak Grove Drive,                   http://scienceandtechnology.jpl.nasa.gov/people/a_mannucci/
 Pasadena, CA 91109

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