pandas.errors.NullFrequencyError#
- exception pandas.errors.NullFrequencyError[source]#
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