from datetime import date, timedelta
import pandas as pd
import numpy as np

def empty(start, end):
	cols = np.array([[d.year, d.month, d.day, 0] for d in [start + timedelta(d) for d in range((end-start).days+1)]]).T
	return pd.DataFrame({'year': cols[0], 'month': cols[1], 'day': cols[2], 'data': cols[3]}).set_index(['year', 'month', 'day'])

empty(date(2017, 7, 1), date(2018, 7, 1))