createNetCDF.py

import numpy as np
import netCDF4 as nc

FILENAME = "./ex001.nc" # File name

DIM1 = 1 # Scalar dimension
DIM2 = 100 # 1-D Array dimension
DIM3 = 20 # Rows matrix
DIM4 = 100 # Columns matrix


def write_file():
    # Open instance file
    nc_file = nc.Dataset(FILENAME, 'w', format="NETCDF4")

    # Define dimensions data
    scalar_dim = nc_file.createDimension('scalarDim', DIM1)
    array_dim = nc_file.createDimension('arrayDim', DIM2)
    rows_matrix_dim = nc_file.createDimension('rowsMatrixDim', DIM3)
    cols_matrix_dim = nc_file.createDimension('colsMatrixDim', DIM4)

    # Define variables data
    scalar_var = nc_file.createVariable(
        'scalarVar', 'float32', ('scalarDim')
    )
    array_var = nc_file.createVariable(
        'arrayVar', 'float32', ('arrayDim')
    )
    rows_mat_var = nc_file.createVariable(
        'rowsMatVar', 'float32', ('rowsMatrixDim')
    )
    cols_mat_var = nc_file.createVariable(
        'colsMatVar', 'float32', ('colsMatrixDim')
    )
    value_mat = nc_file.createVariable(
        'rowsColsVar', 'float32', ('arrayDim', 'rowsMatrixDim', 'colsMatrixDim')
    )
    
    # Assign values
    scalar_var[:] = 42 # Scalar values data
    array_var[:] = np.arange(0, DIM2, 1)+1 # 100 values from 1 to 100
    rows_mat_var[:] = np.arange(0, DIM3, 1)+1 # 20 values from 0 to 20
    cols_mat_var = np.arange(0, DIM4)+1 # 100 values from 0 to 100

    for i in range(DIM2):
        # For each i-th index of array, assign a random matrix (from 0 to 10) of 20x100 dimensions
        value_mat[i, :, :] = np.random.uniform(0, 10, size=(DIM3, DIM4))



def read_file():
    # Open instance file
    nc_file = nc.Dataset(FILENAME, 'r', format="NETCDF4")

    print('Variables...')
    for key in nc_file.variables.keys():
        data_key = nc_file.variables[key]
        print("Variable %s: " % key)
        print("Shape: ", data_key[:].shape)
        print("Value: ", data_key[:])
    # Close instace file
    nc_file.close()


if __name__ == "__main__":
    print("Call function to create file...")
    write_file()
    print("File created")

    print("Reading file...")
    read_file()
    print("Closing file...")