Python3.7 function to plot datetime from timestep of netCDF4

Question

I need to plot bg variable from netcdf file, however the time is expressed as time-step. I read the netcdf file:

data =netCDF4.Dataset (r'D:\Users\NOAA\\CT2019B.molefrac_components_glb3x2_2014-2018.nc')

time = data.variables['time'][:]   
bg   =  data.variables['bg']

time is :

masked_array(data=[5114.0625, 5114.0625, 5114.1875, ..., 6939.8125,
                   6939.9375, 6939.9375],
             mask=False,
       fill_value=1e+20)

units :

'days since 2000-1-1 00:00:00'

plot(time,bg)

I need to convert the x.axis from timestep number to date (2014-01-01 ....)

I tried to convert them as

time = netCDF4.num2date(data.variables['time'][:],data.variables['time'].units)

but, when I to plot it

plot(time,bg)

I received this of error message

TypeError: float() argument must be a string or a number, not 'cftime._cftime.DatetimeGregorian'

Does anyone knows how to solve this issue? Thanks a lot!

Answer 1

You can force num2date to give you Python datetime objects instead:

time = netCDF4.num2date(data.variables['time'][:], data.variables['time'].units,
    only_use_python_datetimes=True)

See the docs for cftime (which is what netCDF4 uses under the hood) for more information.