How can I extract netCDF to csv for a specific location?

Question

I want to extract time series from a NetCDF to csv for a specific location. I got this far with the code but it gives the TypeError: a bytes-like object is required, not 'str'

How can I overcome this issue? Also, will this developed code have as output: time/mwp for the specific location?

import netCDF4 
import pandas as pd
import matplotlib.pyplot as plt
import csv
import numpy as np
from netCDF4 import Dataset, num2date
from pylab import *
import xarray

f = netCDF4.Dataset('Wave_period_global.nc')
f.variables.keys()
print (f)

lat = f.variables['latitude'][:]
lon = f.variables['longitude'][:]
time_var = f.variables['time']
dtime = netCDF4.num2date(time_var[:],time_var.units)
mwp = f.variables['mwp'][:]

print(lon.min(), lon.max())
print(lat.min(), lat.max())

longitude = 172
latitude = 50

def near(array,value):
    idx=(abs(array-value)).argmin()
    return idx

ix = near(lat, latitude)
iy = near(lon, longitude)

print ('Latitude =',ix)
print ('Longitude =',iy)

with open ('Wave_period_global.csv', 'wb') as csvfile:
    filewriter = csv.writer(csvfile, delimiter=',',
                            quotechar='|', quoting=csv.QUOTE_MINIMAL)
    for ln in range(len(lon)):
        for lt in range(len(lat)):
            value=f.variables['mwp'][0][lt][ln]
            dtime = netCDF4.num2date(time_var[0],time_var.units)
            print(dtime,lat[lt],lon[ln,],value)
            filewriter.writerow([dtime,lat[lt],lon[ln,],value])

Answer 1

See my comment above. I'm leaving output as csv out of my answer to focus on your real question.

from netCDF4 import Dataset, num2date

f = netCDF4.Dataset('Wave_period_global.nc')

lat = f.variables['latitude'][:]
lon = f.variables['longitude'][:]
time_var = f.variables['time']
# These are all datetime object.
dtime = netCDF4.num2date(time_var[:],time_var.units)
mwp = f.variables['mwp'][:]

print(lon.min(), lon.max())
print(lat.min(), lat.max())

longitude = 172
latitude = 50

def near(array,value):
    idx=(abs(array-value)).argmin()
    return idx

ix = near(lat, latitude)
iy = near(lon, longitude)

print ('Latitude =',ix)
print ('lat[] =', lat[ix])
print ('Longitude =',iy)
print ('lon[] =', lon[iy])

for i in range(len(dtime)):
  value=f.variables['mwp'][i][ix][iy]
  print(dtime[i],lat[ix],lon[iy,],value)