utils_date.py

# import datetime

# def string_to_date(string):
# 	(y, m, d) = map(int, string.split('-'))
# 	return datetime.date(year=y, month=m, day=d)

# def year_difference(start_date, end_date):
# 	start_ord = start_date.toordinal()
# 	end_ord = end_date.toordinal()
# 	return (end_ord - start_ord) / 365.25

# def year_delta(start_date, years):
# 	days = round(years * 365.25)
# 	delta = datetime.timedelta(days=days)
# 	return start_date + delta

# def numerical_date(date, format = '%Y-%m-%d'):
# 	"""Takes a calendar date and a numerical dates in terms of years"""
# 	"""If date is missing precision, still return numerical date"""
# 	date = date.replace("XX", "01")
# 	if isinstance(date, basestring):
# 		try:
# 			date = datetime.datetime.strptime(date, format).date()
# 		except:
# 			date = datetime.datetime.strptime(date, '%Y-%m-%d').date()
# 	start_date = datetime.date(year=date.year, month=1, day=1)
# 	start_ord = start_date.toordinal()
# 	end_ord = date.toordinal()
# 	return date.year + (end_ord - start_ord) / 365.25
	
# def calendar_date(numerical_date):
# 	"""Takes a numerical date and returns a calendar date"""
# 	year_part = int(numerical_date)
# 	date = datetime.date(year=year_part, month = 1, day = 1)
# 	days = round((numerical_date % 1) * 365.25)
# 	delta = datetime.timedelta(days=days)
# 	return date + delta

# def string_to_numerical_date(string):
# 	date = string_to_date(string)
# 	return numerical_date(date)

# def date_to_day(date):
# 	if isinstance(date, datetime.date):
# 		return date.toordinal()
# 	elif isinstance(date,basestring):
# 		return datetime.datetime.strptime(date, '%Y-%m-%d').toordinal()
# 	elif isinstance(date, int):
# 		return date
# 	else:
# 		print "unknown date format", date
# 		return np.nan

# def main():
# 	date1 = string_to_date('2011-06-12')
# 	date2 = string_to_date('2013-03-15')
# 	print year_difference(date1, date2)
# 	print numerical_date(date1)
# 	print string_to_numerical_date('2014-02-01')

# if __name__ == "__main__":
# 	main()