ENH: Rewrite Canadian treasury loader.

This commit is contained in:
Scott Sanderson
2015-10-22 07:22:35 -04:00
parent 8c38278783
commit c9e165aa2d
+119 -94
View File
@@ -13,113 +13,138 @@
# See the License for the specific language governing permissions and
# limitations under the License.
import datetime
import requests
import pandas as pd
import six
from toolz import curry
from toolz.curried.operator import add as prepend
from . loader_utils import (
source_to_records
)
from zipline.data.treasuries import (
treasury_mappings, get_treasury_date, get_treasury_rate
)
_CURVE_MAPPINGS = {
'date': (get_treasury_date, "Date"),
'1month': (get_treasury_rate, "V39063"),
'3month': (get_treasury_rate, "V39065"),
'6month': (get_treasury_rate, "V39066"),
'1year': (get_treasury_rate, "V39067"),
'2year': (get_treasury_rate, "V39051"),
'3year': (get_treasury_rate, "V39052"),
'5year': (get_treasury_rate, "V39053"),
'7year': (get_treasury_rate, "V39054"),
'10year': (get_treasury_rate, "V39055"),
COLUMN_NAMES = {
"V39063": '1month',
"V39065": '3month',
"V39066": '6month',
"V39067": '1year',
"V39051": '2year',
"V39052": '3year',
"V39053": '5year',
"V39054": '7year',
"V39055": '10year',
# Bank of Canada refers to this as 'Long' Rate, approximately 30 years.
'30year': (get_treasury_rate, "V39056"),
"V39056": '30year',
}
BILL_IDS = ['V39063', 'V39065', 'V39066', 'V39067']
BOND_IDS = ['V39051', 'V39052', 'V39053', 'V39054', 'V39055', 'V39056']
BILLS = ['V39063', 'V39065', 'V39066', 'V39067']
BONDS = ['V39051', 'V39052', 'V39053', 'V39054', 'V39055', 'V39056']
@curry
def _format_url(instrument_type,
instrument_ids,
start_date,
end_date,
earliest_allowed_date):
"""
Format a URL for loading data from Bank of Canada.
"""
return (
"http://www.bankofcanada.ca/stats/results/csv"
"?lP=lookup_{instrument_type}_yields.php"
"&sR={restrict}"
"&se={instrument_ids}"
"&dF={start}"
"&dT={end}".format(
instrument_type=instrument_type,
instrument_ids='-'.join(map(prepend("L_"), instrument_ids)),
restrict=earliest_allowed_date.strftime("%Y-%m-%d"),
start=start_date.strftime("%Y-%m-%d"),
end=end_date.strftime("%Y-%m-%d"),
)
)
format_bill_url = _format_url('tbill', BILL_IDS)
format_bond_url = _format_url('bond', BOND_IDS)
def load_frame(url, skiprows):
"""
Load a DataFrame of data from a Bank of Canada site.
"""
return pd.read_csv(
url,
skiprows=skiprows,
skipinitialspace=True,
na_values=["Bank holiday", "Not available"],
parse_dates=["Date"],
index_col="Date",
).dropna(how='all') \
.tz_localize('UTC') \
.rename(columns=COLUMN_NAMES)
def check_known_inconsistencies(bill_data, bond_data):
"""
There are a couple quirks in the data provided by Bank of Canada.
Check that no new quirks have been introduced in the latest download.
"""
inconsistent_dates = bill_data.index.sym_diff(bond_data.index)
known_inconsistencies = [
# bill_data has an entry for 2010-02-15, which bond_data doesn't.
# bond_data has an entry for 2006-09-04, which bill_data doesn't.
# Both of these dates are bank holidays (Flag Day and Labor Day,
# respectively).
pd.Timestamp('2006-09-04', tz='UTC'),
pd.Timestamp('2010-02-15', tz='UTC'),
# 2013-07-25 comes back as "Not available" from the bills endpoint.
# This date doesn't seem to be a bank holiday, but the previous
# calendar implementation dropped this entry, so we drop it as well.
# If someone cares deeply about the integrity of the Canadian trading
# calendar, they may want to consider forward-filling here rather than
# dropping the row.
pd.Timestamp('2013-07-25', tz='UTC'),
]
unexpected_inconsistences = inconsistent_dates.drop(known_inconsistencies)
if len(unexpected_inconsistences):
in_bills = bill_data.index.difference(bond_data.index).difference(
known_inconsistencies
)
in_bonds = bond_data.index.difference(bill_data.index).difference(
known_inconsistencies
)
raise ValueError(
"Inconsistent dates for Canadian treasury bills vs bonds. \n"
"Dates with bills but not bonds: {in_bills}.\n"
"Dates with bonds but not bills: {in_bonds}.".format(
in_bills=in_bills,
in_bonds=in_bonds,
)
)
def get_treasury_source(start_date=None, end_date=None):
today = datetime.date.today()
# Bank of Canada only has 10 years of data and has this in the URL.
restriction = datetime.date(today.year - 10, today.month, today.day)
today = pd.Timestamp('now').normalize()
# Bank of Canada only has the last 10 years of data at any given time.
earliest_date = today.date().replace(year=today.year - 10)
if not end_date:
end_date = today
if not start_date:
start_date = restriction
start_date = earliest_date
bill_url = (
"http://www.bankofcanada.ca/stats/results/csv?"
"lP=lookup_tbill_yields.php&sR={restrict}&se="
"L_V39063-L_V39065-L_V39066-L_V39067&dF={start}&dT={end}"
.format(restrict=restriction.strftime("%Y-%m-%d"),
start=start_date.strftime("%Y-%m-%d"),
end=end_date.strftime("%Y-%m-%d"),
)
bill_data = load_frame(
format_bill_url(start_date, end_date, earliest_date),
# We skip fewer rows here because we query for fewer bill fields,
# which makes the header smaller.
skiprows=18,
)
bond_url = (
"http://www.bankofcanada.ca/stats/results/csv?"
"lP=lookup_bond_yields.php&sR={restrict}&se="
"L_V39051-L_V39052-L_V39053-L_V39054-L_V39055-L_V39056"
"&dF={start}&dT={end}"
.format(restrict=restriction.strftime("%Y-%m-%d"),
start=start_date.strftime("%Y-%m-%d"),
end=end_date.strftime("%Y-%m-%d")
)
bond_data = load_frame(
format_bond_url(start_date, end_date, earliest_date),
skiprows=22,
)
check_known_inconsistencies(bill_data, bond_data)
res_bill = requests.get(bill_url, stream=True)
res_bond = requests.get(bond_url, stream=True)
bill_iter = res_bill.iter_lines()
bond_iter = res_bond.iter_lines()
# dropna('any') removes the rows for which we only had data for one of
# bills/bonds.
out = pd.concat([bond_data, bill_data], axis=1).dropna(how='any')
assert set(out.columns) == set(six.itervalues(COLUMN_NAMES))
bill_row = ""
while ",".join(BILLS) not in bill_row:
bill_row = bill_iter.next()
if 'Daily series:' in bill_row:
bill_end_date = datetime.datetime.strptime(
bill_row.split(' - ')[1].strip(),
"%Y-%m-%d").date()
bill_header = bill_row.split(",")
bond_row = ""
while ",".join(BONDS) not in bond_row:
bond_row = bond_iter.next()
if 'Daily series:' in bond_row:
bond_end_date = datetime.datetime.strptime(
bond_row.split(' - ')[1].strip(),
"%Y-%m-%d").date()
bond_header = bond_row.split(",")
# Line up the two dates
if bill_end_date > bond_end_date:
bill_iter.next()
elif bond_end_date > bill_end_date:
bond_iter.next()
for bill_row in bill_iter:
bond_row = bond_iter.next()
bill_dict = dict(zip(bill_header, bill_row.split(",")))
bond_dict = dict(zip(bond_header, bond_row.split(",")))
if ' Bank holiday' in bond_row.split(",") + bill_row.split(","):
continue
if ' Not available' in bond_row.split(",") + bill_row.split(","):
continue
bill_dict.update(bond_dict)
yield bill_dict
def get_treasury_data():
mappings = treasury_mappings(_CURVE_MAPPINGS)
source = get_treasury_source()
return source_to_records(mappings, source)
# Multiply by 0.01 to convert from percentages to expected output format.
return out * 0.01