#testing code about difference
f = netcdf.netcdf_file('2m air temperature difference.nc', 'w')
f.history = 'describes the difference in 2m air temperature between the period (1992-2011) to (1961-1981)'
f.createDimension('lons', 192)
f.createDimension('lats', 94)
print 'lons.size', lons.size
print 'lats.size', lats.size
longi = f.createVariable('lons',  'i', ['lons'])
lati = f.createVariable('lats', 'i',  ['lats'])
f.createDimension('diff', difference.size)
lons = lons[:]
lats = lats[:]
differ = difference[:]
f.close()

testing_file = 'C:/Users/ralei/Desktop/2m air temperature difference.nc'
testing_data = Dataset(testing_file, mode = 'r')
test_lati = testing_data.variables['lati'][:]
print test_lati
test_longi = testing_data.variables['longi'][:]
print test_longi