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pandas.Series.dt.is_year_start

Series.dt.is_year_start

Indicate whether the date is the first day of a year.

Returns:
Series or DatetimeIndex

The same type as the original data with boolean values. Series will have the same name and index. DatetimeIndex will have the same name.

See also

is_year_end
Similar property indicating the last day of the year.

Examples

This method is available on Series with datetime values under the .dt accessor, and directly on DatetimeIndex.

>>> dates = pd.Series(pd.date_range("2017-12-30", periods=3))
>>> dates
0   2017-12-30
1   2017-12-31
2   2018-01-01
dtype: datetime64[ns]
>>> dates.dt.is_year_start
0    False
1    False
2    True
dtype: bool
>>> idx = pd.date_range("2017-12-30", periods=3)
>>> idx
DatetimeIndex(['2017-12-30', '2017-12-31', '2018-01-01'],
              dtype='datetime64[ns]', freq='D')
>>> idx.is_year_start
array([False, False,  True])
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