data_support.py 文件源码

def history(self, symbol=None, frequency=None, fields=None, start=None, end=None, length=None, db=None):
        if frequency is None:
            frequency = self.frequency
        try:
            if symbol is None:
                symbol = list(self._panels[frequency].items)
            result = self._read_panel(symbol, frequency, fields, start, end, length)
            if self.match(result, symbol, length):
                return result
            else:
                raise KeyError()
        except KeyError:
            if symbol is None:
                symbol = list(self._panels[self.frequency].items())
            if end is None:
                end = self.time
            result = self._read_db(symbol, frequency, fields, start, end, length, db if db else self._db)
            if isinstance(result, pd.Panel) and len(result.minor_axis) == 1:
                return result.iloc[:, :, 0]
            else:
                return result