Python pandas.tseries.frequencies.get_period_alias() Examples

The following are 27 code examples of pandas.tseries.frequencies.get_period_alias(). You can vote up the ones you like or vote down the ones you don't like, and go to the original project or source file by following the links above each example. You may also want to check out all available functions/classes of the module pandas.tseries.frequencies , or try the search function .
Example #1
Source File: _timeseries.py    From twitter-stock-recommendation with MIT License 6 votes vote down vote up 
def _get_freq(ax, series):
    # get frequency from data
    freq = getattr(series.index, 'freq', None)
    if freq is None:
        freq = getattr(series.index, 'inferred_freq', None)

    ax_freq = _get_ax_freq(ax)

    # use axes freq if no data freq
    if freq is None:
        freq = ax_freq

    # get the period frequency
    if isinstance(freq, DateOffset):
        freq = freq.rule_code
    else:
        freq = frequencies.get_base_alias(freq)

    freq = frequencies.get_period_alias(freq)
    return freq, ax_freq
Example #2
Source File: _timeseries.py    From vnpy_crypto with MIT License 6 votes vote down vote up 
def _get_freq(ax, series):
    # get frequency from data
    freq = getattr(series.index, 'freq', None)
    if freq is None:
        freq = getattr(series.index, 'inferred_freq', None)

    ax_freq = _get_ax_freq(ax)

    # use axes freq if no data freq
    if freq is None:
        freq = ax_freq

    # get the period frequency
    if isinstance(freq, DateOffset):
        freq = freq.rule_code
    else:
        freq = frequencies.get_base_alias(freq)

    freq = frequencies.get_period_alias(freq)
    return freq, ax_freq
Example #3
Source File: _timeseries.py    From coffeegrindsize with MIT License 6 votes vote down vote up 
def _get_freq(ax, series):
    # get frequency from data
    freq = getattr(series.index, 'freq', None)
    if freq is None:
        freq = getattr(series.index, 'inferred_freq', None)

    ax_freq = _get_ax_freq(ax)

    # use axes freq if no data freq
    if freq is None:
        freq = ax_freq

    # get the period frequency
    if isinstance(freq, DateOffset):
        freq = freq.rule_code
    else:
        freq = get_base_alias(freq)

    freq = frequencies.get_period_alias(freq)
    return freq, ax_freq
Example #4
Source File: plotting.py    From Computable with MIT License 6 votes vote down vote up 
def _get_freq(ax, series):
    # get frequency from data
    freq = getattr(series.index, 'freq', None)
    if freq is None:
        freq = getattr(series.index, 'inferred_freq', None)

    ax_freq = getattr(ax, 'freq', None)

    # use axes freq if no data freq
    if freq is None:
        freq = ax_freq

    # get the period frequency
    if isinstance(freq, DateOffset):
        freq = freq.rule_code
    else:
        freq = frequencies.get_base_alias(freq)

    freq = frequencies.get_period_alias(freq)

    return freq
Example #5
Source File: _timeseries.py    From predictive-maintenance-using-machine-learning with Apache License 2.0 6 votes vote down vote up 
def _get_freq(ax, series):
    # get frequency from data
    freq = getattr(series.index, 'freq', None)
    if freq is None:
        freq = getattr(series.index, 'inferred_freq', None)

    ax_freq = _get_ax_freq(ax)

    # use axes freq if no data freq
    if freq is None:
        freq = ax_freq

    # get the period frequency
    if isinstance(freq, DateOffset):
        freq = freq.rule_code
    else:
        freq = get_base_alias(freq)

    freq = frequencies.get_period_alias(freq)
    return freq, ax_freq
Example #6
Source File: _timeseries.py    From elasticintel with GNU General Public License v3.0 6 votes vote down vote up 
def _get_freq(ax, series):
    # get frequency from data
    freq = getattr(series.index, 'freq', None)
    if freq is None:
        freq = getattr(series.index, 'inferred_freq', None)

    ax_freq = _get_ax_freq(ax)

    # use axes freq if no data freq
    if freq is None:
        freq = ax_freq

    # get the period frequency
    if isinstance(freq, DateOffset):
        freq = freq.rule_code
    else:
        freq = frequencies.get_base_alias(freq)

    freq = frequencies.get_period_alias(freq)
    return freq, ax_freq
Example #7
Source File: _timeseries.py    From recruit with Apache License 2.0 6 votes vote down vote up 
def _get_freq(ax, series):
    # get frequency from data
    freq = getattr(series.index, 'freq', None)
    if freq is None:
        freq = getattr(series.index, 'inferred_freq', None)

    ax_freq = _get_ax_freq(ax)

    # use axes freq if no data freq
    if freq is None:
        freq = ax_freq

    # get the period frequency
    if isinstance(freq, DateOffset):
        freq = freq.rule_code
    else:
        freq = get_base_alias(freq)

    freq = frequencies.get_period_alias(freq)
    return freq, ax_freq
Example #8
Source File: _timeseries.py    From Splunking-Crime with GNU Affero General Public License v3.0 6 votes vote down vote up 
def _get_freq(ax, series):
    # get frequency from data
    freq = getattr(series.index, 'freq', None)
    if freq is None:
        freq = getattr(series.index, 'inferred_freq', None)

    ax_freq = _get_ax_freq(ax)

    # use axes freq if no data freq
    if freq is None:
        freq = ax_freq

    # get the period frequency
    if isinstance(freq, DateOffset):
        freq = freq.rule_code
    else:
        freq = frequencies.get_base_alias(freq)

    freq = frequencies.get_period_alias(freq)
    return freq, ax_freq
Example #9
Source File: _timeseries.py    From predictive-maintenance-using-machine-learning with Apache License 2.0 5 votes vote down vote up 
def _maybe_convert_index(ax, data):
    # tsplot converts automatically, but don't want to convert index
    # over and over for DataFrames
    if isinstance(data.index, ABCDatetimeIndex):
        freq = getattr(data.index, 'freq', None)

        if freq is None:
            freq = getattr(data.index, 'inferred_freq', None)
        if isinstance(freq, DateOffset):
            freq = freq.rule_code

        if freq is None:
            freq = _get_ax_freq(ax)

        if freq is None:
            raise ValueError('Could not get frequency alias for plotting')

        freq = get_base_alias(freq)
        freq = frequencies.get_period_alias(freq)

        data = data.to_period(freq=freq)
    return data


# Patch methods for subplot. Only format_dateaxis is currently used.
# Do we need the rest for convenience?
Example #10
Source File: _timeseries.py    From twitter-stock-recommendation with MIT License 5 votes vote down vote up 
def _maybe_convert_index(ax, data):
    # tsplot converts automatically, but don't want to convert index
    # over and over for DataFrames
    if isinstance(data.index, DatetimeIndex):
        freq = getattr(data.index, 'freq', None)

        if freq is None:
            freq = getattr(data.index, 'inferred_freq', None)
        if isinstance(freq, DateOffset):
            freq = freq.rule_code

        if freq is None:
            freq = _get_ax_freq(ax)

        if freq is None:
            raise ValueError('Could not get frequency alias for plotting')

        freq = frequencies.get_base_alias(freq)
        freq = frequencies.get_period_alias(freq)

        data = data.to_period(freq=freq)
    return data


# Patch methods for subplot. Only format_dateaxis is currently used.
# Do we need the rest for convenience?
Example #11
Source File: _timeseries.py    From twitter-stock-recommendation with MIT License 5 votes vote down vote up 
def _use_dynamic_x(ax, data):
    freq = _get_index_freq(data)
    ax_freq = _get_ax_freq(ax)

    if freq is None:  # convert irregular if axes has freq info
        freq = ax_freq
    else:  # do not use tsplot if irregular was plotted first
        if (ax_freq is None) and (len(ax.get_lines()) > 0):
            return False

    if freq is None:
        return False

    if isinstance(freq, DateOffset):
        freq = freq.rule_code
    else:
        freq = frequencies.get_base_alias(freq)
    freq = frequencies.get_period_alias(freq)

    if freq is None:
        return False

    # hack this for 0.10.1, creating more technical debt...sigh
    if isinstance(data.index, DatetimeIndex):
        base = frequencies.get_freq(freq)
        x = data.index
        if (base <= frequencies.FreqGroup.FR_DAY):
            return x[:1].is_normalized
        return Period(x[0], freq).to_timestamp(tz=x.tz) == x[0]
    return True
Example #12
Source File: _timeseries.py    From coffeegrindsize with MIT License 5 votes vote down vote up 
def _maybe_convert_index(ax, data):
    # tsplot converts automatically, but don't want to convert index
    # over and over for DataFrames
    if isinstance(data.index, ABCDatetimeIndex):
        freq = getattr(data.index, 'freq', None)

        if freq is None:
            freq = getattr(data.index, 'inferred_freq', None)
        if isinstance(freq, DateOffset):
            freq = freq.rule_code

        if freq is None:
            freq = _get_ax_freq(ax)

        if freq is None:
            raise ValueError('Could not get frequency alias for plotting')

        freq = get_base_alias(freq)
        freq = frequencies.get_period_alias(freq)

        data = data.to_period(freq=freq)
    return data


# Patch methods for subplot. Only format_dateaxis is currently used.
# Do we need the rest for convenience?
Example #13
Source File: _timeseries.py    From coffeegrindsize with MIT License 5 votes vote down vote up 
def _use_dynamic_x(ax, data):
    freq = _get_index_freq(data)
    ax_freq = _get_ax_freq(ax)

    if freq is None:  # convert irregular if axes has freq info
        freq = ax_freq
    else:  # do not use tsplot if irregular was plotted first
        if (ax_freq is None) and (len(ax.get_lines()) > 0):
            return False

    if freq is None:
        return False

    if isinstance(freq, DateOffset):
        freq = freq.rule_code
    else:
        freq = get_base_alias(freq)
    freq = frequencies.get_period_alias(freq)

    if freq is None:
        return False

    # hack this for 0.10.1, creating more technical debt...sigh
    if isinstance(data.index, ABCDatetimeIndex):
        base = get_freq(freq)
        x = data.index
        if (base <= FreqGroup.FR_DAY):
            return x[:1].is_normalized
        return Period(x[0], freq).to_timestamp(tz=x.tz) == x[0]
    return True
Example #14
Source File: _timeseries.py    From elasticintel with GNU General Public License v3.0 5 votes vote down vote up 
def _maybe_convert_index(ax, data):
    # tsplot converts automatically, but don't want to convert index
    # over and over for DataFrames
    if isinstance(data.index, DatetimeIndex):
        freq = getattr(data.index, 'freq', None)

        if freq is None:
            freq = getattr(data.index, 'inferred_freq', None)
        if isinstance(freq, DateOffset):
            freq = freq.rule_code

        if freq is None:
            freq = _get_ax_freq(ax)

        if freq is None:
            raise ValueError('Could not get frequency alias for plotting')

        freq = frequencies.get_base_alias(freq)
        freq = frequencies.get_period_alias(freq)

        data = data.to_period(freq=freq)
    return data


# Patch methods for subplot. Only format_dateaxis is currently used.
# Do we need the rest for convenience?
Example #15
Source File: _timeseries.py    From elasticintel with GNU General Public License v3.0 5 votes vote down vote up 
def _use_dynamic_x(ax, data):
    freq = _get_index_freq(data)
    ax_freq = _get_ax_freq(ax)

    if freq is None:  # convert irregular if axes has freq info
        freq = ax_freq
    else:  # do not use tsplot if irregular was plotted first
        if (ax_freq is None) and (len(ax.get_lines()) > 0):
            return False

    if freq is None:
        return False

    if isinstance(freq, DateOffset):
        freq = freq.rule_code
    else:
        freq = frequencies.get_base_alias(freq)
    freq = frequencies.get_period_alias(freq)

    if freq is None:
        return False

    # hack this for 0.10.1, creating more technical debt...sigh
    if isinstance(data.index, DatetimeIndex):
        base = frequencies.get_freq(freq)
        x = data.index
        if (base <= frequencies.FreqGroup.FR_DAY):
            return x[:1].is_normalized
        return Period(x[0], freq).to_timestamp(tz=x.tz) == x[0]
    return True
Example #16
Source File: _timeseries.py    From Splunking-Crime with GNU Affero General Public License v3.0 5 votes vote down vote up 
def _maybe_convert_index(ax, data):
    # tsplot converts automatically, but don't want to convert index
    # over and over for DataFrames
    if isinstance(data.index, DatetimeIndex):
        freq = getattr(data.index, 'freq', None)

        if freq is None:
            freq = getattr(data.index, 'inferred_freq', None)
        if isinstance(freq, DateOffset):
            freq = freq.rule_code

        if freq is None:
            freq = _get_ax_freq(ax)

        if freq is None:
            raise ValueError('Could not get frequency alias for plotting')

        freq = frequencies.get_base_alias(freq)
        freq = frequencies.get_period_alias(freq)

        data = data.to_period(freq=freq)
    return data


# Patch methods for subplot. Only format_dateaxis is currently used.
# Do we need the rest for convenience?
Example #17
Source File: _timeseries.py    From Splunking-Crime with GNU Affero General Public License v3.0 5 votes vote down vote up 
def _use_dynamic_x(ax, data):
    freq = _get_index_freq(data)
    ax_freq = _get_ax_freq(ax)

    if freq is None:  # convert irregular if axes has freq info
        freq = ax_freq
    else:  # do not use tsplot if irregular was plotted first
        if (ax_freq is None) and (len(ax.get_lines()) > 0):
            return False

    if freq is None:
        return False

    if isinstance(freq, DateOffset):
        freq = freq.rule_code
    else:
        freq = frequencies.get_base_alias(freq)
    freq = frequencies.get_period_alias(freq)

    if freq is None:
        return False

    # hack this for 0.10.1, creating more technical debt...sigh
    if isinstance(data.index, DatetimeIndex):
        base = frequencies.get_freq(freq)
        x = data.index
        if (base <= frequencies.FreqGroup.FR_DAY):
            return x[:1].is_normalized
        return Period(x[0], freq).to_timestamp(tz=x.tz) == x[0]
    return True
Example #18
Source File: _timeseries.py    From predictive-maintenance-using-machine-learning with Apache License 2.0 5 votes vote down vote up 
def _use_dynamic_x(ax, data):
    freq = _get_index_freq(data)
    ax_freq = _get_ax_freq(ax)

    if freq is None:  # convert irregular if axes has freq info
        freq = ax_freq
    else:  # do not use tsplot if irregular was plotted first
        if (ax_freq is None) and (len(ax.get_lines()) > 0):
            return False

    if freq is None:
        return False

    if isinstance(freq, DateOffset):
        freq = freq.rule_code
    else:
        freq = get_base_alias(freq)
    freq = frequencies.get_period_alias(freq)

    if freq is None:
        return False

    # hack this for 0.10.1, creating more technical debt...sigh
    if isinstance(data.index, ABCDatetimeIndex):
        base = get_freq(freq)
        x = data.index
        if (base <= FreqGroup.FR_DAY):
            return x[:1].is_normalized
        return Period(x[0], freq).to_timestamp(tz=x.tz) == x[0]
    return True
Example #19
Source File: plotting.py    From Computable with MIT License 5 votes vote down vote up 
def _maybe_convert_index(self, data):
        # tsplot converts automatically, but don't want to convert index
        # over and over for DataFrames
        from pandas.core.frame import DataFrame
        if (isinstance(data.index, DatetimeIndex) and
                isinstance(data, DataFrame)):
            freq = getattr(data.index, 'freq', None)

            if freq is None:
                freq = getattr(data.index, 'inferred_freq', None)
            if isinstance(freq, DateOffset):
                freq = freq.rule_code
            freq = get_base_alias(freq)
            freq = get_period_alias(freq)

            if freq is None:
                ax = self._get_ax(0)
                freq = getattr(ax, 'freq', None)

            if freq is None:
                raise ValueError('Could not get frequency alias for plotting')

            data = DataFrame(data.values,
                             index=data.index.to_period(freq=freq),
                             columns=data.columns)
        return data
Example #20
Source File: plotting.py    From Computable with MIT License 5 votes vote down vote up 
def _is_dynamic_freq(self, freq):
        if isinstance(freq, DateOffset):
            freq = freq.rule_code
        else:
            freq = get_base_alias(freq)
        freq = get_period_alias(freq)
        return freq is not None and self._no_base(freq)
Example #21
Source File: _timeseries.py    From vnpy_crypto with MIT License 5 votes vote down vote up 
def _maybe_convert_index(ax, data):
    # tsplot converts automatically, but don't want to convert index
    # over and over for DataFrames
    if isinstance(data.index, DatetimeIndex):
        freq = getattr(data.index, 'freq', None)

        if freq is None:
            freq = getattr(data.index, 'inferred_freq', None)
        if isinstance(freq, DateOffset):
            freq = freq.rule_code

        if freq is None:
            freq = _get_ax_freq(ax)

        if freq is None:
            raise ValueError('Could not get frequency alias for plotting')

        freq = frequencies.get_base_alias(freq)
        freq = frequencies.get_period_alias(freq)

        data = data.to_period(freq=freq)
    return data


# Patch methods for subplot. Only format_dateaxis is currently used.
# Do we need the rest for convenience?
Example #22
Source File: _timeseries.py    From vnpy_crypto with MIT License 5 votes vote down vote up 
def _use_dynamic_x(ax, data):
    freq = _get_index_freq(data)
    ax_freq = _get_ax_freq(ax)

    if freq is None:  # convert irregular if axes has freq info
        freq = ax_freq
    else:  # do not use tsplot if irregular was plotted first
        if (ax_freq is None) and (len(ax.get_lines()) > 0):
            return False

    if freq is None:
        return False

    if isinstance(freq, DateOffset):
        freq = freq.rule_code
    else:
        freq = frequencies.get_base_alias(freq)
    freq = frequencies.get_period_alias(freq)

    if freq is None:
        return False

    # hack this for 0.10.1, creating more technical debt...sigh
    if isinstance(data.index, DatetimeIndex):
        base = frequencies.get_freq(freq)
        x = data.index
        if (base <= frequencies.FreqGroup.FR_DAY):
            return x[:1].is_normalized
        return Period(x[0], freq).to_timestamp(tz=x.tz) == x[0]
    return True
Example #23
Source File: _timeseries.py    From recruit with Apache License 2.0 5 votes vote down vote up 
def _maybe_convert_index(ax, data):
    # tsplot converts automatically, but don't want to convert index
    # over and over for DataFrames
    if isinstance(data.index, ABCDatetimeIndex):
        freq = getattr(data.index, 'freq', None)

        if freq is None:
            freq = getattr(data.index, 'inferred_freq', None)
        if isinstance(freq, DateOffset):
            freq = freq.rule_code

        if freq is None:
            freq = _get_ax_freq(ax)

        if freq is None:
            raise ValueError('Could not get frequency alias for plotting')

        freq = get_base_alias(freq)
        freq = frequencies.get_period_alias(freq)

        data = data.to_period(freq=freq)
    return data


# Patch methods for subplot. Only format_dateaxis is currently used.
# Do we need the rest for convenience?
Example #24
Source File: _timeseries.py    From recruit with Apache License 2.0 5 votes vote down vote up 
def _use_dynamic_x(ax, data):
    freq = _get_index_freq(data)
    ax_freq = _get_ax_freq(ax)

    if freq is None:  # convert irregular if axes has freq info
        freq = ax_freq
    else:  # do not use tsplot if irregular was plotted first
        if (ax_freq is None) and (len(ax.get_lines()) > 0):
            return False

    if freq is None:
        return False

    if isinstance(freq, DateOffset):
        freq = freq.rule_code
    else:
        freq = get_base_alias(freq)
    freq = frequencies.get_period_alias(freq)

    if freq is None:
        return False

    # hack this for 0.10.1, creating more technical debt...sigh
    if isinstance(data.index, ABCDatetimeIndex):
        base = get_freq(freq)
        x = data.index
        if (base <= FreqGroup.FR_DAY):
            return x[:1].is_normalized
        return Period(x[0], freq).to_timestamp(tz=x.tz) == x[0]
    return True
Example #25
Source File: datetimes.py    From predictive-maintenance-using-machine-learning with Apache License 2.0 4 votes vote down vote up 
def to_period(self, freq=None):
        """
        Cast to PeriodArray/Index at a particular frequency.

        Converts DatetimeArray/Index to PeriodArray/Index.

        Parameters
        ----------
        freq : string or Offset, optional
            One of pandas' :ref:`offset strings <timeseries.offset_aliases>`
            or an Offset object. Will be inferred by default.

        Returns
        -------
        PeriodArray/Index

        Raises
        ------
        ValueError
            When converting a DatetimeArray/Index with non-regular values,
            so that a frequency cannot be inferred.

        See Also
        --------
        PeriodIndex: Immutable ndarray holding ordinal values.
        DatetimeIndex.to_pydatetime: Return DatetimeIndex as object.

        Examples
        --------
        >>> df = pd.DataFrame({"y": [1,2,3]},
        ...                   index=pd.to_datetime(["2000-03-31 00:00:00",
        ...                                         "2000-05-31 00:00:00",
        ...                                         "2000-08-31 00:00:00"]))
        >>> df.index.to_period("M")
        PeriodIndex(['2000-03', '2000-05', '2000-08'],
                    dtype='period[M]', freq='M')

        Infer the daily frequency

        >>> idx = pd.date_range("2017-01-01", periods=2)
        >>> idx.to_period()
        PeriodIndex(['2017-01-01', '2017-01-02'],
                    dtype='period[D]', freq='D')
        """
        from pandas.core.arrays import PeriodArray

        if self.tz is not None:
            warnings.warn("Converting to PeriodArray/Index representation "
                          "will drop timezone information.", UserWarning)

        if freq is None:
            freq = self.freqstr or self.inferred_freq

            if freq is None:
                raise ValueError("You must pass a freq argument as "
                                 "current index has none.")

            freq = get_period_alias(freq)

        return PeriodArray._from_datetime64(self._data, freq, tz=self.tz)
Example #26
Source File: datetimes.py    From vnpy_crypto with MIT License 4 votes vote down vote up 
def to_period(self, freq=None):
        """
        Cast to PeriodIndex at a particular frequency.

        Converts DatetimeIndex to PeriodIndex.

        Parameters
        ----------
        freq : string or Offset, optional
            One of pandas' :ref:`offset strings <timeseries.offset_aliases>`
            or an Offset object. Will be inferred by default.

        Returns
        -------
        PeriodIndex

        Raises
        ------
        ValueError
            When converting a DatetimeIndex with non-regular values, so that a
            frequency cannot be inferred.

        Examples
        --------
        >>> df = pd.DataFrame({"y": [1,2,3]},
        ...                   index=pd.to_datetime(["2000-03-31 00:00:00",
        ...                                         "2000-05-31 00:00:00",
        ...                                         "2000-08-31 00:00:00"]))
        >>> df.index.to_period("M")
        PeriodIndex(['2000-03', '2000-05', '2000-08'],
                    dtype='period[M]', freq='M')

        Infer the daily frequency

        >>> idx = pd.date_range("2017-01-01", periods=2)
        >>> idx.to_period()
        PeriodIndex(['2017-01-01', '2017-01-02'],
                    dtype='period[D]', freq='D')

        See also
        --------
        pandas.PeriodIndex: Immutable ndarray holding ordinal values
        pandas.DatetimeIndex.to_pydatetime: Return DatetimeIndex as object
        """
        from pandas.core.indexes.period import PeriodIndex

        if freq is None:
            freq = self.freqstr or self.inferred_freq

            if freq is None:
                msg = ("You must pass a freq argument as "
                       "current index has none.")
                raise ValueError(msg)

            freq = get_period_alias(freq)

        return PeriodIndex(self.values, name=self.name, freq=freq, tz=self.tz)
Example #27
Source File: datetimes.py    From recruit with Apache License 2.0 4 votes vote down vote up 
def to_period(self, freq=None):
        """
        Cast to PeriodArray/Index at a particular frequency.

        Converts DatetimeArray/Index to PeriodArray/Index.

        Parameters
        ----------
        freq : string or Offset, optional
            One of pandas' :ref:`offset strings <timeseries.offset_aliases>`
            or an Offset object. Will be inferred by default.

        Returns
        -------
        PeriodArray/Index

        Raises
        ------
        ValueError
            When converting a DatetimeArray/Index with non-regular values,
            so that a frequency cannot be inferred.

        See Also
        --------
        PeriodIndex: Immutable ndarray holding ordinal values.
        DatetimeIndex.to_pydatetime: Return DatetimeIndex as object.

        Examples
        --------
        >>> df = pd.DataFrame({"y": [1,2,3]},
        ...                   index=pd.to_datetime(["2000-03-31 00:00:00",
        ...                                         "2000-05-31 00:00:00",
        ...                                         "2000-08-31 00:00:00"]))
        >>> df.index.to_period("M")
        PeriodIndex(['2000-03', '2000-05', '2000-08'],
                    dtype='period[M]', freq='M')

        Infer the daily frequency

        >>> idx = pd.date_range("2017-01-01", periods=2)
        >>> idx.to_period()
        PeriodIndex(['2017-01-01', '2017-01-02'],
                    dtype='period[D]', freq='D')
        """
        from pandas.core.arrays import PeriodArray

        if self.tz is not None:
            warnings.warn("Converting to PeriodArray/Index representation "
                          "will drop timezone information.", UserWarning)

        if freq is None:
            freq = self.freqstr or self.inferred_freq

            if freq is None:
                raise ValueError("You must pass a freq argument as "
                                 "current index has none.")

            freq = get_period_alias(freq)

        return PeriodArray._from_datetime64(self._data, freq, tz=self.tz)