# xarray.CFTimeIndex ### *class* xarray.CFTimeIndex(data, name=None, \*\*kwargs)[[source]](https://github.com/pydata/xarray/blob/main/xarray/coding/cftimeindex.py#L229-L806) Custom Index for working with CF calendars and dates All elements of a CFTimeIndex must be cftime.datetime objects. * **Parameters:** * **data** ([array](https://numpy.org/doc/stable/glossary.html#term-array) or [`CFTimeIndex`](#xarray.CFTimeIndex)) – Sequence of cftime.datetime objects to use in index * **name** ([`str`](https://docs.python.org/3/builtins/stdtypes.html#str), *default*: [`None`](https://docs.python.org/3/builtins/constants.html#None)) – Name of the resulting index #### SEE ALSO [`date_range`](xarray.date_range.html.md#xarray.date_range) #### \_\_init_\_() ### Methods | [`__init__`](#xarray.CFTimeIndex.__init__)() | | |-------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------| | [`all`](xarray.CFTimeIndex.all.html.md#xarray.CFTimeIndex.all)(\*args, \*\*kwargs) | Return whether all elements are Truthy. | | [`any`](xarray.CFTimeIndex.any.html.md#xarray.CFTimeIndex.any)(\*args, \*\*kwargs) | Return whether any element is Truthy. | | [`append`](xarray.CFTimeIndex.append.html.md#xarray.CFTimeIndex.append)(other) | Append a collection of Index options together. | | [`argmax`](xarray.CFTimeIndex.argmax.html.md#xarray.CFTimeIndex.argmax)([axis, skipna]) | Return int position of the largest value in the Index. | | [`argmin`](xarray.CFTimeIndex.argmin.html.md#xarray.CFTimeIndex.argmin)([axis, skipna]) | Return int position of the smallest value in the Index. | | [`argsort`](xarray.CFTimeIndex.argsort.html.md#xarray.CFTimeIndex.argsort)(\*args, \*\*kwargs) | Return the integer indices that would sort the index. | | [`asof`](xarray.CFTimeIndex.asof.html.md#xarray.CFTimeIndex.asof)(label) | Return the label from the index, or, if not present, the previous one. | | [`asof_locs`](xarray.CFTimeIndex.asof_locs.html.md#xarray.CFTimeIndex.asof_locs)(where, mask) | Return the locations (indices) of labels in the index. | | [`astype`](xarray.CFTimeIndex.astype.html.md#xarray.CFTimeIndex.astype)(dtype[, copy]) | Create an Index with values cast to dtypes. | | [`ceil`](xarray.CFTimeIndex.ceil.html.md#xarray.CFTimeIndex.ceil)(freq) | Round dates up to fixed frequency. | | [`contains`](xarray.CFTimeIndex.contains.html.md#xarray.CFTimeIndex.contains)(key) | Needed for .loc based partial-string indexing | | [`copy`](xarray.CFTimeIndex.copy.html.md#xarray.CFTimeIndex.copy)([name, deep]) | Make a copy of this object. | | [`delete`](xarray.CFTimeIndex.delete.html.md#xarray.CFTimeIndex.delete)(loc) | Make new Index with passed location(-s) deleted. | | `diff`([periods]) | Computes the difference between consecutive values in the Index object. | | [`difference`](xarray.CFTimeIndex.difference.html.md#xarray.CFTimeIndex.difference)(other[, sort]) | Return a new Index with elements of index not in other. | | [`drop`](xarray.CFTimeIndex.drop.html.md#xarray.CFTimeIndex.drop)(labels[, errors]) | Make new Index with passed list of labels deleted. | | [`drop_duplicates`](xarray.CFTimeIndex.drop_duplicates.html.md#xarray.CFTimeIndex.drop_duplicates)(\*[, keep]) | Return Index with duplicate values removed. | | [`droplevel`](xarray.CFTimeIndex.droplevel.html.md#xarray.CFTimeIndex.droplevel)([level]) | Return index with requested level(s) removed. | | [`dropna`](xarray.CFTimeIndex.dropna.html.md#xarray.CFTimeIndex.dropna)([how]) | Return Index without NA/NaN values. | | [`duplicated`](xarray.CFTimeIndex.duplicated.html.md#xarray.CFTimeIndex.duplicated)([keep]) | Indicate duplicate index values. | | [`equals`](xarray.CFTimeIndex.equals.html.md#xarray.CFTimeIndex.equals)(other) | Determine if two Index object are equal. | | [`factorize`](xarray.CFTimeIndex.factorize.html.md#xarray.CFTimeIndex.factorize)([sort, use_na_sentinel]) | Encode the object as an enumerated type or categorical variable. | | [`fillna`](xarray.CFTimeIndex.fillna.html.md#xarray.CFTimeIndex.fillna)(value) | Fill NA/NaN values with the specified value. | | [`floor`](xarray.CFTimeIndex.floor.html.md#xarray.CFTimeIndex.floor)(freq) | Round dates down to fixed frequency. | | [`get_indexer`](xarray.CFTimeIndex.get_indexer.html.md#xarray.CFTimeIndex.get_indexer)(target[, method, limit, tolerance]) | Compute indexer and mask for new index given the current index. | | [`get_indexer_for`](xarray.CFTimeIndex.get_indexer_for.html.md#xarray.CFTimeIndex.get_indexer_for)(target) | Guaranteed return of an indexer even when non-unique. | | [`get_indexer_non_unique`](xarray.CFTimeIndex.get_indexer_non_unique.html.md#xarray.CFTimeIndex.get_indexer_non_unique)(target) | Compute indexer and mask for new index given the current index. | | [`get_level_values`](xarray.CFTimeIndex.get_level_values.html.md#xarray.CFTimeIndex.get_level_values)(level) | Return an Index of values for requested level. | | [`get_loc`](xarray.CFTimeIndex.get_loc.html.md#xarray.CFTimeIndex.get_loc)(key) | Adapted from pandas.tseries.index.DatetimeIndex.get_loc | | [`get_slice_bound`](xarray.CFTimeIndex.get_slice_bound.html.md#xarray.CFTimeIndex.get_slice_bound)(label, side) | Calculate slice bound that corresponds to given label. | | [`get_value`](xarray.CFTimeIndex.get_value.html.md#xarray.CFTimeIndex.get_value)(series, key) | Adapted from pandas.tseries.index.DatetimeIndex.get_value | | [`groupby`](xarray.CFTimeIndex.groupby.html.md#xarray.CFTimeIndex.groupby)(values) | Group the index labels by a given array of values. | | [`identical`](xarray.CFTimeIndex.identical.html.md#xarray.CFTimeIndex.identical)(other) | Similar to equals, but checks that object attributes and types are also equal. | | `infer_objects`([copy]) | If we have an object dtype, try to infer a non-object dtype. | | [`insert`](xarray.CFTimeIndex.insert.html.md#xarray.CFTimeIndex.insert)(loc, item) | Make new Index inserting new item at location. | | [`intersection`](xarray.CFTimeIndex.intersection.html.md#xarray.CFTimeIndex.intersection)(other[, sort]) | Form the intersection of two Index objects. | | [`is_`](xarray.CFTimeIndex.is_.html.md#xarray.CFTimeIndex.is_)(other) | More flexible, faster check like `is` but that works through views. | | [`isin`](xarray.CFTimeIndex.isin.html.md#xarray.CFTimeIndex.isin)(values[, level]) | Return a boolean array where the index values are in values. | | [`isna`](xarray.CFTimeIndex.isna.html.md#xarray.CFTimeIndex.isna)() | Detect missing values. | | [`isnull`](xarray.CFTimeIndex.isnull.html.md#xarray.CFTimeIndex.isnull)() | Detect missing values. | | [`item`](xarray.CFTimeIndex.item.html.md#xarray.CFTimeIndex.item)() | Return the first element of the underlying data as a Python scalar. | | [`join`](xarray.CFTimeIndex.join.html.md#xarray.CFTimeIndex.join)(other, \*[, how, level, ...]) | Compute join_index and indexers to conform data structures to the new index. | | [`map`](xarray.CFTimeIndex.map.html.md#xarray.CFTimeIndex.map)(mapper[, na_action]) | Map values using an input mapping or function. | | [`max`](xarray.CFTimeIndex.max.html.md#xarray.CFTimeIndex.max)([axis, skipna]) | Return the maximum value of the Index. | | [`memory_usage`](xarray.CFTimeIndex.memory_usage.html.md#xarray.CFTimeIndex.memory_usage)([deep]) | Memory usage of the values. | | [`min`](xarray.CFTimeIndex.min.html.md#xarray.CFTimeIndex.min)([axis, skipna]) | Return the minimum value of the Index. | | [`notna`](xarray.CFTimeIndex.notna.html.md#xarray.CFTimeIndex.notna)() | Detect existing (non-missing) values. | | [`notnull`](xarray.CFTimeIndex.notnull.html.md#xarray.CFTimeIndex.notnull)() | Detect existing (non-missing) values. | | [`nunique`](xarray.CFTimeIndex.nunique.html.md#xarray.CFTimeIndex.nunique)([dropna]) | Return number of unique elements in the object. | | [`putmask`](xarray.CFTimeIndex.putmask.html.md#xarray.CFTimeIndex.putmask)(mask, value) | Return a new Index of the values set with the mask. | | [`ravel`](xarray.CFTimeIndex.ravel.html.md#xarray.CFTimeIndex.ravel)([order]) | Return a view on self. | | [`reindex`](xarray.CFTimeIndex.reindex.html.md#xarray.CFTimeIndex.reindex)(target[, method, level, limit, ...]) | Create index with target's values. | | [`rename`](xarray.CFTimeIndex.rename.html.md#xarray.CFTimeIndex.rename)(name, \*[, inplace]) | Alter Index or MultiIndex name. | | [`repeat`](xarray.CFTimeIndex.repeat.html.md#xarray.CFTimeIndex.repeat)(repeats[, axis]) | Repeat elements of an Index. | | [`round`](xarray.CFTimeIndex.round.html.md#xarray.CFTimeIndex.round)(freq) | Round dates to a fixed frequency. | | [`searchsorted`](xarray.CFTimeIndex.searchsorted.html.md#xarray.CFTimeIndex.searchsorted)(value[, side, sorter]) | Find indices where elements should be inserted to maintain order. | | [`set_names`](xarray.CFTimeIndex.set_names.html.md#xarray.CFTimeIndex.set_names)(names, \*[, level, inplace]) | Set Index or MultiIndex name. | | [`shift`](xarray.CFTimeIndex.shift.html.md#xarray.CFTimeIndex.shift)(periods[, freq]) | Shift the CFTimeIndex a multiple of the given frequency. | | [`slice_indexer`](xarray.CFTimeIndex.slice_indexer.html.md#xarray.CFTimeIndex.slice_indexer)([start, end, step]) | Compute the slice indexer for input labels and step. | | [`slice_locs`](xarray.CFTimeIndex.slice_locs.html.md#xarray.CFTimeIndex.slice_locs)([start, end, step]) | Compute slice locations for input labels. | | [`sort_values`](xarray.CFTimeIndex.sort_values.html.md#xarray.CFTimeIndex.sort_values)(\*[, return_indexer, ascending, ...]) | Return a sorted copy of the index. | | [`sortlevel`](xarray.CFTimeIndex.sortlevel.html.md#xarray.CFTimeIndex.sortlevel)([level, ascending, ...]) | For internal compatibility with the Index API. | | [`strftime`](xarray.CFTimeIndex.strftime.html.md#xarray.CFTimeIndex.strftime)(date_format) | Return an Index of formatted strings specified by date_format, which supports the same string format as the python standard library. | | [`symmetric_difference`](xarray.CFTimeIndex.symmetric_difference.html.md#xarray.CFTimeIndex.symmetric_difference)(other[, result_name, sort]) | Compute the symmetric difference of two Index objects. | | [`take`](xarray.CFTimeIndex.take.html.md#xarray.CFTimeIndex.take)(indices[, axis, allow_fill, fill_value]) | Return a new Index of the values selected by the indices. | | [`to_datetimeindex`](xarray.CFTimeIndex.to_datetimeindex.html.md#xarray.CFTimeIndex.to_datetimeindex)([unsafe, time_unit]) | If possible, convert this index to a pandas.DatetimeIndex. | | [`to_flat_index`](xarray.CFTimeIndex.to_flat_index.html.md#xarray.CFTimeIndex.to_flat_index)() | Identity method. | | [`to_frame`](xarray.CFTimeIndex.to_frame.html.md#xarray.CFTimeIndex.to_frame)([index, name]) | Create a DataFrame with a column containing the Index. | | [`to_list`](xarray.CFTimeIndex.to_list.html.md#xarray.CFTimeIndex.to_list)() | Return a list of the values. | | [`to_numpy`](xarray.CFTimeIndex.to_numpy.html.md#xarray.CFTimeIndex.to_numpy)([dtype, copy, na_value]) | A NumPy ndarray representing the values in this Series or Index. | | [`to_series`](xarray.CFTimeIndex.to_series.html.md#xarray.CFTimeIndex.to_series)([index, name]) | Create a Series with both index and values equal to the index keys. | | [`tolist`](xarray.CFTimeIndex.tolist.html.md#xarray.CFTimeIndex.tolist)() | Return a list of the values. | | [`transpose`](xarray.CFTimeIndex.transpose.html.md#xarray.CFTimeIndex.transpose)(\*args, \*\*kwargs) | Return the transpose, which is by definition self. | | [`union`](xarray.CFTimeIndex.union.html.md#xarray.CFTimeIndex.union)(other[, sort]) | Form the union of two Index objects. | | [`unique`](xarray.CFTimeIndex.unique.html.md#xarray.CFTimeIndex.unique)([level]) | Return unique values in the index. | | [`value_counts`](xarray.CFTimeIndex.value_counts.html.md#xarray.CFTimeIndex.value_counts)([normalize, sort, ascending, ...]) | Return a Series containing counts of unique values. | | [`view`](xarray.CFTimeIndex.view.html.md#xarray.CFTimeIndex.view)([cls]) | Return a view of the Index with the specified dtype or a new Index instance. | | [`where`](xarray.CFTimeIndex.where.html.md#xarray.CFTimeIndex.where)(cond[, other]) | Replace values where the condition is False. | ### Attributes | [`T`](xarray.CFTimeIndex.T.html.md#xarray.CFTimeIndex.T) | Return the transpose, which is by definition self. | |---------------------------------------------------------------------------------------------------------------------|------------------------------------------------------------------| | [`array`](xarray.CFTimeIndex.array.html.md#xarray.CFTimeIndex.array) | The ExtensionArray of the data backing this Index. | | [`asi8`](xarray.CFTimeIndex.asi8.html.md#xarray.CFTimeIndex.asi8) | Convert to integers with units of microseconds since 1970-01-01. | | [`calendar`](xarray.CFTimeIndex.calendar.html.md#xarray.CFTimeIndex.calendar) | The calendar used by the datetimes in the index. | | [`date_type`](xarray.CFTimeIndex.date_type.html.md#xarray.CFTimeIndex.date_type) | | | [`day`](xarray.CFTimeIndex.day.html.md#xarray.CFTimeIndex.day) | The days of the datetime | | [`day_of_week`](xarray.CFTimeIndex.day_of_week.html.md#xarray.CFTimeIndex.day_of_week) | The day of week of the datetime | | [`day_of_year`](xarray.CFTimeIndex.day_of_year.html.md#xarray.CFTimeIndex.day_of_year) | The ordinal day of year of the datetime | | [`dayofweek`](xarray.CFTimeIndex.dayofweek.html.md#xarray.CFTimeIndex.dayofweek) | The day of week of the datetime | | [`dayofyear`](xarray.CFTimeIndex.dayofyear.html.md#xarray.CFTimeIndex.dayofyear) | The ordinal day of year of the datetime | | [`days_in_month`](xarray.CFTimeIndex.days_in_month.html.md#xarray.CFTimeIndex.days_in_month) | The number of days in the month of the datetime | | [`dtype`](xarray.CFTimeIndex.dtype.html.md#xarray.CFTimeIndex.dtype) | Return the dtype object of the underlying data. | | [`empty`](xarray.CFTimeIndex.empty.html.md#xarray.CFTimeIndex.empty) | Indicator whether Index is empty. | | [`freq`](xarray.CFTimeIndex.freq.html.md#xarray.CFTimeIndex.freq) | The frequency used by the dates in the index. | | [`has_duplicates`](xarray.CFTimeIndex.has_duplicates.html.md#xarray.CFTimeIndex.has_duplicates) | Check if the Index has duplicate values. | | [`hasnans`](xarray.CFTimeIndex.hasnans.html.md#xarray.CFTimeIndex.hasnans) | Return True if there are any NaNs. | | [`hour`](xarray.CFTimeIndex.hour.html.md#xarray.CFTimeIndex.hour) | The hours of the datetime | | [`inferred_type`](xarray.CFTimeIndex.inferred_type.html.md#xarray.CFTimeIndex.inferred_type) | Return a string of the type inferred from the values. | | `is_leap_year` | | | [`is_monotonic_decreasing`](xarray.CFTimeIndex.is_monotonic_decreasing.html.md#xarray.CFTimeIndex.is_monotonic_decreasing) | Return a boolean if the values are equal or decreasing. | | [`is_monotonic_increasing`](xarray.CFTimeIndex.is_monotonic_increasing.html.md#xarray.CFTimeIndex.is_monotonic_increasing) | Return a boolean if the values are equal or increasing. | | [`is_unique`](xarray.CFTimeIndex.is_unique.html.md#xarray.CFTimeIndex.is_unique) | Return if the index has unique values. | | [`microsecond`](xarray.CFTimeIndex.microsecond.html.md#xarray.CFTimeIndex.microsecond) | The microseconds of the datetime | | [`minute`](xarray.CFTimeIndex.minute.html.md#xarray.CFTimeIndex.minute) | The minutes of the datetime | | [`month`](xarray.CFTimeIndex.month.html.md#xarray.CFTimeIndex.month) | The month of the datetime | | [`name`](xarray.CFTimeIndex.name.html.md#xarray.CFTimeIndex.name) | Return Index or MultiIndex name. | | [`names`](xarray.CFTimeIndex.names.html.md#xarray.CFTimeIndex.names) | Get names on index. | | [`nbytes`](xarray.CFTimeIndex.nbytes.html.md#xarray.CFTimeIndex.nbytes) | Return the number of bytes in the underlying data. | | [`ndim`](xarray.CFTimeIndex.ndim.html.md#xarray.CFTimeIndex.ndim) | Number of dimensions of the underlying data, by definition 1. | | [`nlevels`](xarray.CFTimeIndex.nlevels.html.md#xarray.CFTimeIndex.nlevels) | Number of levels. | | [`second`](xarray.CFTimeIndex.second.html.md#xarray.CFTimeIndex.second) | The seconds of the datetime | | [`shape`](xarray.CFTimeIndex.shape.html.md#xarray.CFTimeIndex.shape) | Return a tuple of the shape of the underlying data. | | [`size`](xarray.CFTimeIndex.size.html.md#xarray.CFTimeIndex.size) | Return the number of elements in the underlying data. | | [`values`](xarray.CFTimeIndex.values.html.md#xarray.CFTimeIndex.values) | Return an array representing the data in the Index. | | [`year`](xarray.CFTimeIndex.year.html.md#xarray.CFTimeIndex.year) | The year of the datetime |