calculate total energy accumulation from insolation measurements

energy.py

# wow. energy.
#
# grab source data from http://www-k12.atmos.washington.edu/k12/grayskies/nw_weather.html

import csv
from datetime import datetime, timedelta

MINS_IN_DAY=1440

fp = open( "LFEM_data-.csv" )
rd = csv.reader( fp )

# skip the header
rd.next()

day_totals = {}

for i, (julain,reading_datetime_str,solar_str) in enumerate(rd):
    if i%MINS_IN_DAY==0: 
        print i//MINS_IN_DAY
    
    try:
        solar = float(solar_str)
        reading_dt = datetime.strptime(reading_datetime_str, "%Y-%m-%d %H:%M")-timedelta(hours=8)
    except ValueError, e:
        continue
    
    day = (reading_dt.year,reading_dt.month,reading_dt.day)
    day_totals[day] = day_totals.get(day,0) + solar*60

    
day_totals = sorted( day_totals.items(), key=lambda x:x[0] )

fp = open( "totals.csv", "w" )
for day,total in day_totals:
    day_of_year = datetime(*day).strftime("%j")
    fp.write( "%s,%s,%s\n"%(day_of_year,"%s-%s-%s"%day, total) )