Plotting Battery Status from Datawell waverider spt files using pandas

plot_battery.py

import os
import matplotlib.pyplot as plt
import pandas as pd
fig = plt.figure(figsize=(20,10), dpi=100)
from datetime import datetime
os.chdir('/path/to/buoy_name/year/')

date_index = []
battery_status = []
months = os.listdir('.')
for month in months:
    try:
        os.chdir(month)
        dir_listing = os.listdir('.')
        for file_name in dir_listing:
            if '$' not in file_name:
                if file_name.endswith('.spt'):
                    date_index.append(datetime.strptime(file_name.split('}')[1][:-4], '%Y-%m-%dT%Hh%MZ'))
                    battery_status.append(int(open(file_name).readlines()[6:7][0].strip()))
        os.chdir('..')
    except:
        print "problem"
battery_status_df = pd.DataFrame(battery_status, columns = ['battery_staus'], index=date_index)       
battery_status_df.plot()
plt.show()