Method _with_freq

pandas/core/arrays/datetimelike.py:2448–2475

Helper to get a view on the same data, with a new freq. Parameters ---------- freq : DateOffset, None, or "infer" Returns ------- Same type as self

(self, freq)

        self._freq = None

    def _with_freq(self, freq) -> Self:
        """
        Helper to get a view on the same data, with a new freq.

        Parameters
        ----------
        freq : DateOffset, None, or "infer"

        Returns
        -------
        Same type as self
        """
        # GH#29843
        if freq is None:
            # Always valid
            pass
        elif len(self) == 0 and isinstance(freq, BaseOffset):
            # Always valid.  In the TimedeltaArray case, we require a Tick offset
            if self.dtype.kind == "m" and not isinstance(freq, (Tick, Day)):
                raise TypeError("TimedeltaArray/Index freq must be a Tick")
        else:
            # As an internal method, we can ensure this assertion always holds
            assert freq == "infer"
            freq = to_offset(self.inferred_freq)

        arr = self.view()
        arr._freq = freq
        return arr

    # --------------------------------------------------------------
    # ExtensionArray Interface