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# pandas.tseries.offsets.DateOffset

class pandas.tseries.offsets.DateOffset

  Standard kind of date increment used for a date range.

  Works exactly like the keyword argument form of relativedelta. Note that the positional argument form of relativedelata is not supported. Use of the keyword n is discouraged– you would be better off specifying n in the keywords you use, but regardless it is there for you. n is needed for DateOffset subclasses.

  DateOffset works as follows. Each offset specify a set of dates that conform to the DateOffset. For example, Bday defines this set to be the set of dates that are weekdays (M-F). To test if a date is in the set of a DateOffset dateOffset we can use the is_on_offset method: dateOffset.is_on_offset(date).

  If a date is not on a valid date, the rollback and rollforward methods can be used to roll the date to the nearest valid date before/after the date.

  DateOffsets can be created to move dates forward a given number of valid dates. For example, Bday(2) can be added to a date to move it two business days forward. If the date does not start on a valid date, first it is moved to a valid date. Thus pseudo code is:

      def __add__(date):
        date = rollback(date) # does nothing if date is valid
        return date + <n number of periods>

  When a date offset is created for a negative number of periods, the date is first rolled forward. The pseudo code is:

      def __add__(date):
        date = rollforward(date) # does nothing if date is valid
        return date + <n number of periods>

  Zero presents a problem. Should it roll forward or back? We arbitrarily have it rollforward:

  date + BDay(0) == BDay.rollforward(date)

  Since 0 is a bit weird, we suggest avoiding its use.

  Besides, adding a DateOffsets specified by the singular form of the date component can be used to replace certain component of the timestamp.

  Parameters:
    nint, default 1

      The number of time periods the offset represents. If specified without a temporal pattern, defaults to n days.

    normalizebool, default False

      Whether to round the result of a DateOffset addition down to the previous midnight.

    weekdayint {0, 1, …, 6}, default 0

      A specific integer for the day of the week.

      - 0 is Monday

      - 1 is Tuesday

      - 2 is Wednesday

      - 3 is Thursday

      - 4 is Friday

      - 5 is Saturday

      - 6 is Sunday

      Instead Weekday type from dateutil.relativedelta can be used.

      - MO is Monday

      - TU is Tuesday

      - WE is Wednesday

      - TH is Thursday

      - FR is Friday

      - SA is Saturday

      - SU is Sunday.

    **kwds

      Temporal parameter that add to or replace the offset value.

      Parameters that add to the offset (like Timedelta):

      - years

      - months

      - weeks

      - days

      - hours

      - minutes

      - seconds

      - milliseconds

      - microseconds

      - nanoseconds

      Parameters that replace the offset value:

      - year

      - month

      - day

      - weekday

      - hour

      - minute

      - second

      - microsecond

      - nanosecond.

  See also

  `dateutil.relativedelta.relativedelta`

    The relativedelta type is designed to be applied to an existing datetime an can replace specific components of that datetime, or represents an interval of time.

  Examples

      >>> from pandas.tseries.offsets import DateOffset
      >>> ts = pd.Timestamp('2017-01-01 09:10:11')
      >>> ts + DateOffset(months=3)
      Timestamp('2017-04-01 09:10:11')

      >>> ts = pd.Timestamp('2017-01-01 09:10:11')
      >>> ts + DateOffset(months=2)
      Timestamp('2017-03-01 09:10:11')
      >>> ts + DateOffset(day=31)
      Timestamp('2017-01-31 09:10:11')

      >>> ts + pd.DateOffset(hour=8)
      Timestamp('2017-01-01 08:10:11')

  Attributes

  `base` | Returns a copy of the calling offset object with n=1 and all other attributes equal.
  `freqstr` | Return a string representing the frequency.
  `kwds` | Return a dict of extra parameters for the offset.
  `n` |
  `name` | Return a string representing the base frequency.
  `nanos` |
  `normalize` |
  `rule_code` |

  Methods

  `copy`() | Return a copy of the frequency.
  `is_anchored`() | (DEPRECATED) Return boolean whether the frequency is a unit frequency (n=1).
  `is_month_end`(ts) | Return boolean whether a timestamp occurs on the month end.
  `is_month_start`(ts) | Return boolean whether a timestamp occurs on the month start.
  `is_on_offset`(dt) | Return boolean whether a timestamp intersects with this frequency.
  `is_quarter_end`(ts) | Return boolean whether a timestamp occurs on the quarter end.
  `is_quarter_start`(ts) | Return boolean whether a timestamp occurs on the quarter start.
  `is_year_end`(ts) | Return boolean whether a timestamp occurs on the year end.
  `is_year_start`(ts) | Return boolean whether a timestamp occurs on the year start.
  `rollback`(dt) | Roll provided date backward to next offset only if not on offset.
  `rollforward`(dt) | Roll provided date forward to next offset only if not on offset.