# xarray.cftime_range

`xarray.``cftime_range`(start=None, end=None, periods=None, freq='D', normalize=False, name=None, closed=None, calendar='standard')

  Return a fixed frequency CFTimeIndex.

  Parameters:

  - start (str or cftime.datetime, optional) – Left bound for generating dates.
  - end (str or cftime.datetime, optional) – Right bound for generating dates.
  - periods (integer, optional) – Number of periods to generate.
  - freq (str, default 'D', BaseCFTimeOffset, or None) – Frequency strings can have multiples, e.g. ‘5H’.
  - normalize (bool, default False) – Normalize start/end dates to midnight before generating date range.
  - name (str, default None) – Name of the resulting index
  - closed ({None, 'left', 'right'}, optional) – Make the interval closed with respect to the given frequency to the ‘left’, ‘right’, or both sides (None, the default).
  - calendar (str) – Calendar type for the datetimes (default ‘standard’).

  Returns: |
  Return type: | CFTimeIndex

  Notes

  This function is an analog of `pandas.date_range` for use in generating sequences of `cftime.datetime` objects. It supports most of the features of `pandas.date_range` (e.g. specifying how the index is `closed` on either side, or whether or not to `normalize` the start and end bounds); however, there are some notable exceptions:

  - You cannot specify a `tz` (time zone) argument.
  - Start or end dates specified as partial-datetime strings must use the ISO-8601 format.
  - It supports many, but not all, frequencies supported by `pandas.date_range`. For example it does not currently support any of the business-related, semi-monthly, or sub-second frequencies.
  - Compound sub-monthly frequencies are not supported, e.g. ‘1H1min’, as these can easily be written in terms of the finest common resolution, e.g. ‘61min’.

  Valid simple frequency strings for use with `cftime`-calendars include any multiples of the following.

  Alias | Description
  --- | ---
  A, Y | Year-end frequency
  AS, YS | Year-start frequency
  Q | Quarter-end frequency
  QS | Quarter-start frequency
  M | Month-end frequency
  MS | Month-start frequency
  D | Day frequency
  H | Hour frequency
  T, min | Minute frequency
  S | Second frequency

  Any multiples of the following anchored offsets are also supported.

  Alias | Description
  --- | ---
  A(S)-JAN | Annual frequency, anchored at the end (or beginning) of January
  A(S)-FEB | Annual frequency, anchored at the end (or beginning) of February
  A(S)-MAR | Annual frequency, anchored at the end (or beginning) of March
  A(S)-APR | Annual frequency, anchored at the end (or beginning) of April
  A(S)-MAY | Annual frequency, anchored at the end (or beginning) of May
  A(S)-JUN | Annual frequency, anchored at the end (or beginning) of June
  A(S)-JUL | Annual frequency, anchored at the end (or beginning) of July
  A(S)-AUG | Annual frequency, anchored at the end (or beginning) of August
  A(S)-SEP | Annual frequency, anchored at the end (or beginning) of September
  A(S)-OCT | Annual frequency, anchored at the end (or beginning) of October
  A(S)-NOV | Annual frequency, anchored at the end (or beginning) of November
  A(S)-DEC | Annual frequency, anchored at the end (or beginning) of December
  Q(S)-JAN | Quarter frequency, anchored at the end (or beginning) of January
  Q(S)-FEB | Quarter frequency, anchored at the end (or beginning) of February
  Q(S)-MAR | Quarter frequency, anchored at the end (or beginning) of March
  Q(S)-APR | Quarter frequency, anchored at the end (or beginning) of April
  Q(S)-MAY | Quarter frequency, anchored at the end (or beginning) of May
  Q(S)-JUN | Quarter frequency, anchored at the end (or beginning) of June
  Q(S)-JUL | Quarter frequency, anchored at the end (or beginning) of July
  Q(S)-AUG | Quarter frequency, anchored at the end (or beginning) of August
  Q(S)-SEP | Quarter frequency, anchored at the end (or beginning) of September
  Q(S)-OCT | Quarter frequency, anchored at the end (or beginning) of October
  Q(S)-NOV | Quarter frequency, anchored at the end (or beginning) of November
  Q(S)-DEC | Quarter frequency, anchored at the end (or beginning) of December

  Finally, the following calendar aliases are supported.

  Alias | Date type
  --- | ---
  standard, gregorian | `cftime.DatetimeGregorian`
  proleptic_gregorian | `cftime.DatetimeProlepticGregorian`
  noleap, 365_day | `cftime.DatetimeNoLeap`
  all_leap, 366_day | `cftime.DatetimeAllLeap`
  360_day | `cftime.Datetime360Day`
  julian | `cftime.DatetimeJulian`

  Examples

  This function returns a `CFTimeIndex`, populated with `cftime.datetime` objects associated with the specified calendar type, e.g.

      >>> xr.cftime_range(start='2000', periods=6, freq='2MS', calendar='noleap')
      CFTimeIndex([2000-01-01 00:00:00, 2000-03-01 00:00:00, 2000-05-01 00:00:00,
                   2000-07-01 00:00:00, 2000-09-01 00:00:00, 2000-11-01 00:00:00],
                  dtype='object')

  As in the standard pandas function, three of the `start`, `end`, `periods`, or `freq` arguments must be specified at a given time, with the other set to `None`. See the pandas documentation for more examples of the behavior of `date_range` with each of the parameters.

  See also

  `pandas.date_range()`