Source code for tradingstrategy.utils.time

"""Helpers to timestamp format and value conformity.

- We are operating on naive Python datetimes, all in UTC timezone

"""
import calendar
import datetime

import pandas as pd

#: Pre-instiated no difference pd.Tiemdelta for optimisation
ZERO_TIMEDELTA = pd.Timedelta(0)

[docs]def is_compatible_timestamp(ts: pd.Timestamp) -> bool: """Ensure Pandas Timestamp is naive. We do not carry timezone information in data, because it would slow us down. """ assert isinstance(ts, pd.Timestamp), f"We assume pandas.Timestamp, but received {ts}" return ts.tz is None
[docs]def assert_compatible_timestamp(ts: pd.Timestamp): """Check we do not get in bad input timestamps. :raise: AssertionError if the timestamp object is incompatible """ assert isinstance(ts, pd.Timestamp), f"not pd.Timestamp: {ts.__class__.__name__}={ts}" assert is_compatible_timestamp(ts), f"Received pandas.Timestamp in incompatible format: {type(ts)}: {ts}"
[docs]def to_int_unix_timestamp(dt: datetime.datetime) -> int: """Get datetime as UTC seconds since epoch.""" # https://stackoverflow.com/a/5499906/315168 return int(calendar.timegm(dt.utctimetuple()))
[docs]def generate_monthly_timestamps(start: datetime.datetime, end: datetime.datetime) -> list[int]: """Generate timestamps from the start to the end. One timestamp per month. :param start: Start date :param end: End date :return: List of timestamps """ # TODO: ensure index has no missing dates i.e. evenly spaced intervals throughout the period timestamps = [] current_date = start while current_date <= end: timestamps.append(int(current_date.timestamp())) # Check if adding one month stays within the year if current_date.month == 12: current_date = current_date.replace(year=current_date.year + 1, month=1) else: current_date = current_date.replace(month=current_date.month + 1) if current_date > end: timestamps.append(int(end.timestamp())) break return timestamps
[docs]def naive_utcnow() -> datetime.datetime: """Get utcnow() but without timezone information. Fixes for Python 3.12 compatibility - https://blog.miguelgrinberg.com/post/it-s-time-for-a-change-datetime-utcnow-is-now-deprecated """ return datetime.datetime.now(datetime.timezone.utc).replace(tzinfo=None)
[docs]def naive_utcfromtimestamp(timestamp: float | int) -> datetime.datetime: """Get naive UTC datetime from UNIX time. Fixes for Python 3.12 compatibility - https://blog.miguelgrinberg.com/post/it-s-time-for-a-change-datetime-utcnow-is-now-deprecated """ return datetime.datetime.fromtimestamp(timestamp, datetime.timezone.utc).replace(tzinfo=None)
[docs]def get_prior_timestamp(series: pd.Series, ts: pd.Timestamp) -> pd.Timestamp | None: """Get the first timestamp in the index that is before the given timestamp. :return: Any timestamp from the index that is before or at the same time of the given timestamp. Return ``None`` if there are no earlier timestamps. """ index = series.index try: return index[index < ts][-1] except IndexError: return None