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# pandas.errors.NullFrequencyError

exception pandas.errors.NullFrequencyError

  Exception raised when a `freq` cannot be null.

  Particularly `DatetimeIndex.shift`, `TimedeltaIndex.shift`, `PeriodIndex.shift`.

  Examples

      >>> df = pd.DatetimeIndex(["2011-01-01 10:00", "2011-01-01"], freq=None)
      >>> df.shift(2)
      Traceback (most recent call last):
      NullFrequencyError: Cannot shift with no freq