otp.Empty#

class Empty(db=utils.adaptive_to_default, symbol=utils.adaptive_to_default, tick_type=utils.adaptive, start=utils.adaptive, end=utils.adaptive, schema=None, query_parameters=None, **kwargs)#

Bases: Source

Empty data source

Parameters:

  • db (str) – Name of the database from which to take schema.

  • symbol (str, list of str, Source, query, eval query) – Symbol(s) from which data should be taken.

  • tick_type (str,) – Name of the tick_type from which to take schema.

  • start (datetime.datetime, otp.datetime, onetick.py.adaptive) – Time interval from which the data should be taken.

  • end (datetime.datetime, otp.datetime, onetick.py.adaptive) – Time interval from which the data should be taken.

  • schema (dict) – Schema to use in case db and/or tick_type are not set.

  • query_parameters (otp.QueryParameters) – Additional query properties to be set in the resulting .otq file. They will be used if they are not overridden by other parameters or in otp.run.

  • kwargs – Deprecated. Use schema instead. Schema to use in case db and/or tick_type are not set.

Examples

We can define schema:

>>> data = otp.Empty(schema={'A': str, 'B': int})
>>> otp.run(data)
Empty DataFrame
Columns: [A, B, Time]
Index: []
>>> data.schema
{'A': <class 'str'>, 'B': <class 'int'>}

Or we can get schema from the database:

>>> data = otp.Empty(db='SOME_DB', tick_type='TT')
>>> data.schema
{'X': <class 'int'>}