Hi,
[:] - retreives all the values to memory (gives you numpy array)
but queuing the variable should work too, since it is not a good idea to
load everything to the memory if you do not need it all.
I meant the point after variables.["varName"] (but that's probably nothing)
good luck
Cheers
-- Oleksandr 2012/7/5 Carmen St. Jean <carmen.stjean@noaa.gov> > Hi Oleksandr, > > While I have to admit I don't understand your entire response, for > example the bit about reversing elements, your suggestion of accessing > the variable with "[:]" worked! I changed line 4 of my code so it > reads: > > zval = f.variables["zval"][:] # instead of zval = f.variables["zval"] > > Now, when I run the code, it doesn't fail here like before: > > zvalDirectMissingVal = zval[0, 1, 64387] > > When I print zvalDirectMissingVal, then I see "---", which is correct. > > Perhaps you were suggesting something slightly different, but in > either case the mystery seems somewhat solved. Still, it's kind of > strange. If I was able to read most values of zval without the "[:]" > at the end of the variable extraction, then I don't understand why I > couldn't read all values this way. > > Thanks for your help, > > Carmen > > On Tue, Jul 3, 2012 at 6:05 PM, Oleksandr Huziy <guziy.sasha@gmail.com> > wrote: > > Hi Carmen, > > > > I am not sure if this is important, but I don't see the point in your > code > > as described here: > > > > Get the data in a variable object into a NumPy array > > > > If the variable is not scalar (rank > 0): > > > > data = f.variables.['varName'][:] > > > > or > > > > data = f.variables.['varName'],get_value() > > > > Assuming the shape of the variable is (5,20,30) get a slice along the > first > > element of the first dimension: > > > > var = f.variables.['varName'] > > data = var[0] > > > > Get the same slice but reverse the elements of the second dimension. The > > following two statements are equivalent: > > > > data = var[0,::-1,:] > > data = var[0,19::-1,:] > > > > > > I would test it myself but Nio (which I installed using macports), does > not > > work on my system. > > > > Another option for you would be to try netcdf4-python > > > > Cheers > > > > -- > > Oleksandr (Sasha) Huziy > > > > > > > > 2012/7/3 Carmen St. Jean <carmen.stjean@noaa.gov> > >> > >> Hello all, > >> > >> I'm getting this strange error message when I attempt to run the > >> attached code with this input file > >> > >> ( > http://jetstreak.unh.edu/netcdf/nos.creofs.fields.nowcast.20120625.t12z.nc > , > >> it is over one GB in size): > >> > >> Traceback (most recent call last): > >> File "creofstest.py", line 22, in <module> > >> zvalDirectMissingVal = zval[0, 1, 64387] > >> File "/usr/local/lib/python2.7/site-packages/PyNIO/Nio.py", line > >> 305, in __getitem__ > >> ret = _fill_value_to_masked(self,ret) > >> File "/usr/local/lib/python2.7/site-packages/PyNIO/Nio.py", line > >> 283, in _fill_value_to_masked > >> a = ma.masked_where(a == self.__dict__['_FillValue'],a,copy=0) > >> File "/usr/local/lib/python2.7/site-packages/numpy/ma/core.py", line > >> 1802, in masked_where > >> " (got %s and %s)" % (cshape, ashape)) > >> IndexError: Inconsistant shape between the condition and the input > >> (got (1,) and ()) > >> > >> My code is very simple; it's just trying to access the zval variable > >> at different valid indices. > >> > >> I can directly access a specific value from the zval variable that > >> happens to not contain the missing value (e.g., zval[0, 0, 64387]) > >> without a problem. But when I try to directly access a value that I > >> know to be a missing value (e.g., zval[0, 1, 64387]), then I get the > >> above error. > >> > >> I am, however, able to indirectly access that value zval[0, 1, 64387] > >> by saving zval[0, :, 64387] to a new variable and taking the 1st index > >> of that. This correctly prints out as a missing value. > >> > >> Does anyone have any ideas of why this might be happening? > >> > >> Thanks, > >> > >> Carmen > >> > >> _______________________________________________ > >> pyngl-talk mailing list > >> List instructions, subscriber options, unsubscribe: > >> http://mailman.ucar.edu/mailman/listinfo/pyngl-talk > >> > > >
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Received on Thu Jul 5 14:58:34 2012
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