I would like to make a copy of netcdf file using Python.
There are very nice examples of how to read or write netcdf-file, but perhaps there is also a good way how to make the input and then output of the variables to another file.
A good-simple method would be nice, in order to get the dimensions and dimension variables to the output file with the lowest cost.
I found the answer to this question at python netcdf: making a copy of all variables and attributes but one, but I needed to change it to work with my version of python/netCDF4 (Python 2.7.6/1.0.4). If you needed to add or subtract elements, you would make the appropriate modifications.
import netCDF4 as nc
def create_file_from_source(src_file, trg_file):
src = nc.Dataset(src_file)
trg = nc.Dataset(trg_file, mode='w')
# Create the dimensions of the file
for name, dim in src.dimensions.items():
trg.createDimension(name, len(dim) if not dim.isunlimited() else None)
# Copy the global attributes
trg.setncatts({a:src.getncattr(a) for a in src.ncattrs()})
# Create the variables in the file
for name, var in src.variables.items():
trg.createVariable(name, var.dtype, var.dimensions)
# Copy the variable attributes
trg.variables[name].setncatts({a:var.getncattr(a) for a in var.ncattrs()})
# Copy the variables values (as 'f4' eventually)
trg.variables[name][:] = src.variables[name][:]
# Save the file
trg.close()
create_file_from_source('in.nc', 'out.nc')
This snippet has been tested.