Method convert

pandas/io/pytables.py:2240–2305

Convert the data from this selection to the appropriate pandas type.

(
        self, values: np.ndarray, nan_rep, encoding: str, errors: str
    )

        return getattr(self.table.cols, self.cname).is_indexed

    def convert(
        self, values: np.ndarray, nan_rep, encoding: str, errors: str
    ) -> tuple[np.ndarray, np.ndarray] | tuple[Index, Index]:
        """
        Convert the data from this selection to the appropriate pandas type.
        """
        assert isinstance(values, np.ndarray), type(values)

        # values is a recarray
        if values.dtype.fields is not None:
            # Copy, otherwise values will be a view
            # preventing the original recarry from being free'ed
            values = values[self.cname].copy()

        val_kind = self.kind
        values = _maybe_convert(values, val_kind, encoding, errors)
        kwargs = {}
        kwargs["name"] = self.index_name

        if self.freq is not None:
            kwargs["freq"] = self.freq

        factory: type[Index | DatetimeIndex] = Index
        if lib.is_np_dtype(values.dtype, "M") or isinstance(
            values.dtype, DatetimeTZDtype
        ):
            factory = DatetimeIndex
        elif values.dtype == "i8" and "freq" in kwargs:
            # PeriodIndex data is stored as i8
            # error: Incompatible types in assignment (expression has type
            # "Callable[[Any, KwArg(Any)], PeriodIndex]", variable has type
            # "Union[Type[Index], Type[DatetimeIndex]]")
            factory = lambda x, **kwds: PeriodIndex.from_ordinals(  # type: ignore[assignment]
                x, freq=kwds.get("freq", None)
            )._rename(kwds["name"])

        # making an Index instance could throw a number of different errors
        try:
            new_pd_index = factory(values, **kwargs)
        except UnicodeEncodeError as err:
            if (
                errors == "surrogatepass"
                and using_string_dtype()
                and str(err).endswith("surrogates not allowed")
                and HAS_PYARROW
            ):
                new_pd_index = factory(
                    values,
                    dtype=StringDtype(storage="python", na_value=np.nan),
                    **kwargs,
                )
            else:
                raise
        except ValueError:
            # if the output freq is different that what we recorded,
            # it should be None (see also 'doc example part 2')
            if "freq" in kwargs:
                kwargs["freq"] = None