Files
catalyst/zipline/pipeline/loaders/utils.py
T

231 lines
7.7 KiB
Python

import datetime
import numpy as np
import pandas as pd
from six import iteritems
from six.moves import zip
from zipline.utils.numpy_utils import np_NaT
def next_date_frame(dates, events_by_sid):
"""
Make a DataFrame representing the simulated next known date for an event.
Parameters
----------
dates : pd.DatetimeIndex.
The index of the returned DataFrame.
events_by_sid : dict[int -> pd.Series]
Dict mapping sids to a series of dates. Each k:v pair of the series
represents the date we learned of the event mapping to the date the
event will occur.
Returns
-------
next_events: pd.DataFrame
A DataFrame where each column is a security from `events_by_sid` where
the values are the dates of the next known event with the knowledge we
had on the date of the index. Entries falling after the last date will
have `NaT` as the result in the output.
See Also
--------
previous_date_frame
"""
cols = {
equity: np.full_like(dates, np_NaT) for equity in events_by_sid
}
raw_dates = dates.values
for equity, event_dates in iteritems(events_by_sid):
data = cols[equity]
if not event_dates.index.is_monotonic_increasing:
event_dates = event_dates.sort_index()
# Iterate over the raw Series values, since we're comparing against
# numpy arrays anyway.
iterkv = zip(event_dates.index.values, event_dates.values)
for knowledge_date, event_date in iterkv:
date_mask = (
(knowledge_date <= raw_dates) &
(raw_dates <= event_date)
)
value_mask = (event_date <= data) | (data == np_NaT)
data[date_mask & value_mask] = event_date
return pd.DataFrame(index=dates, data=cols)
def previous_date_frame(date_index, events_by_sid):
"""
Make a DataFrame representing simulated next earnings date_index.
Parameters
----------
date_index : DatetimeIndex.
The index of the returned DataFrame.
events_by_sid : dict[int -> DatetimeIndex]
Dict mapping sids to a series of dates. Each k:v pair of the series
represents the date we learned of the event mapping to the date the
event will occur.
Returns
-------
previous_events: pd.DataFrame
A DataFrame where each column is a security from `events_by_sid` where
the values are the dates of the previous event that occured on the date
of the index. Entries falling before the first date will have `NaT` as
the result in the output.
See Also
--------
next_date_frame
"""
sids = list(events_by_sid)
out = np.full((len(date_index), len(sids)), np_NaT, dtype='datetime64[ns]')
dn = date_index[-1].asm8
for col_idx, sid in enumerate(sids):
# events_by_sid[sid] is Series mapping knowledge_date to actual
# event_date. We don't care about the knowledge date for
# computing previous earnings.
values = events_by_sid[sid].values
values = values[values <= dn]
out[date_index.searchsorted(values), col_idx] = values
frame = pd.DataFrame(out, index=date_index, columns=sids)
frame.ffill(inplace=True)
return frame
def normalize_data_query_time(dt, time, tz):
"""Apply the correct time and timezone to a date.
Parameters
----------
dt : pd.Timestamp
The original datetime that represents the date.
time : datetime.time
The time of day to use as the cutoff point for new data. Data points
that you learn about after this time will become available to your
algorithm on the next trading day.
tz : tzinfo
The timezone to normalize your dates to before comparing against
`time`.
Returns
-------
query_dt : pd.Timestamp
The timestamp with the correct time and date in utc.
"""
# merge the correct date with the time in the given timezone then convert
# back to utc
return pd.Timestamp(
datetime.datetime.combine(dt.date(), time),
tz=tz,
).tz_convert('utc')
def normalize_data_query_bounds(lower, upper, time, tz):
"""Adjust the first and last dates in the requested datetime index based on
the provided query time and tz.
lower : pd.Timestamp
The lower date requested.
upper : pd.Timestamp
The upper date requested.
time : datetime.time
The time of day to use as the cutoff point for new data. Data points
that you learn about after this time will become available to your
algorithm on the next trading day.
tz : tzinfo
The timezone to normalize your dates to before comparing against
`time`.
"""
# Subtract one day to grab things that happened on the first day we are
# requesting. This doesn't need to be a trading day, we are only adding
# a lower bound to limit the amount of in memory filtering that needs
# to happen.
lower -= datetime.timedelta(days=1)
if time is not None:
return normalize_data_query_time(
lower,
time,
tz,
), normalize_data_query_time(
upper,
time,
tz,
)
return lower, upper
def normalize_timestamp_to_query_time(df,
time,
tz,
inplace=False,
ts_field='timestamp'):
"""Update the timestamp field of a dataframe to normalize dates around
some data query time/timezone.
Parameters
----------
df : pd.DataFrame
The dataframe to update. This needs a column named ``ts_field``.
time : datetime.time
The time of day to use as the cutoff point for new data. Data points
that you learn about after this time will become available to your
algorithm on the next trading day.
tz : tzinfo
The timezone to normalize your dates to before comparing against
`time`.
inplace : bool, optional
Update the dataframe in place.
ts_field : str, optional
The name of the timestamp field in ``df``.
Returns
-------
df : pd.DataFrame
The dataframe with the timestamp field normalized. If ``inplace`` is
true, then this will be the same object as ``df`` otherwise this will
be a copy.
"""
if not inplace:
# don't mutate the dataframe in place
df = df.copy()
dtidx = pd.DatetimeIndex(df.loc[:, ts_field], tz='utc')
dtidx_local_time = dtidx.tz_convert(tz)
to_roll_forward = dtidx_local_time.time >= time
# for all of the times that are greater than our query time add 1
# day and truncate to the date
df.loc[to_roll_forward, ts_field] = (
dtidx_local_time[to_roll_forward] + datetime.timedelta(days=1)
).normalize().tz_localize(None).tz_localize('utc') # cast back to utc
df.loc[~to_roll_forward, ts_field] = dtidx[~to_roll_forward].normalize()
return df
def check_data_query_args(data_query_time, data_query_tz):
"""Checks the data_query_time and data_query_tz arguments for loaders
and raises a standard exception if one is None and the other is not.
Parameters
----------
data_query_time : datetime.time or None
data_query_tz : tzinfo or None
Raises
------
ValueError
Raised when only one of the arguments is None.
"""
if (data_query_time is None) ^ (data_query_tz is None):
raise ValueError(
"either 'data_query_time' and 'data_query_tz' must both be"
" None or neither may be None (got %r, %r)" % (
data_query_time,
data_query_tz,
),
)