import csv
from datetime import datetime
class DataPoint(namedtuple('DataPoint', ['date', 'value'])):
__slots__ = ()
def __le__(self, other):
return self.value <= other.value
def __lt__(self, other):
return self.value < other.value
def __gt__(self, other):
return self.value > other.value
def read_prices(csvfile, _strptime=datetime.strptime):
with open(csvfile) as infile:
reader = csv.DictReader(infile)
for row in reader:
yield DataPoint(date=_strptime(row['Date'], '%Y-%m-%d').date(),
value=float(row['Adj Close']))
prices = tuple(read_prices('SP500.csv'))