Add docstrings for ExtensionArray methods

Added docstrings for several methods in the ExtensionArray class, including _concat_same_type, searchsorted, shift, and fillna, to improve documentation clarity and usability.

Author: AnonToky

pandas/core/arrays/_mixins.py

@@ -229,30 +229,155 @@ def unique(self) -> Self:
         return self._from_backing_data(new_data)
 
     @classmethod
-    @doc(ExtensionArray._concat_same_type)
     def _concat_same_type(
         cls,
         to_concat: Sequence[Self],
         axis: AxisInt = 0,
     ) -> Self:
+        """
+        Concatenate multiple array of this dtype.
+
+        Parameters
+        ----------
+        to_concat : sequence of this type
+            An array of the same dtype to concatenate.
+
+        Returns
+        -------
+        ExtensionArray
+
+        See Also
+        --------
+        api.extensions.ExtensionArray._explode : Transform each element of
+            list-like to a row.
+        api.extensions.ExtensionArray._formatter : Formatting function for
+            scalar values.
+        api.extensions.ExtensionArray._from_factorized : Reconstruct an
+            ExtensionArray after factorization.
+
+        Examples
+        --------
+        >>> arr1 = pd.array([1, 2, 3])
+        >>> arr2 = pd.array([4, 5, 6])
+        >>> pd.arrays.IntegerArray._concat_same_type([arr1, arr2])
+        <IntegerArray>
+        [1, 2, 3, 4, 5, 6]
+        Length: 6, dtype: Int64
+        """
         if not lib.dtypes_all_equal([x.dtype for x in to_concat]):
             dtypes = {str(x.dtype) for x in to_concat}
             raise ValueError("to_concat must have the same dtype", dtypes)
 
         return super()._concat_same_type(to_concat, axis=axis)
 
-    @doc(ExtensionArray.searchsorted)
     def searchsorted(
         self,
         value: NumpyValueArrayLike | ExtensionArray,
         side: Literal["left", "right"] = "left",
         sorter: NumpySorter | None = None,
     ) -> npt.NDArray[np.intp] | np.intp:
-        npvalue = self._validate_setitem_value(value)
-        return self._ndarray.searchsorted(npvalue, side=side, sorter=sorter)
+        """
+        Find indices where elements should be inserted to maintain order.
+
+        Find the indices into a sorted array `self` (a) such that, if the
+        corresponding elements in `value` were inserted before the indices,
+        the order of `self` would be preserved.
+
+        Assuming that `self` is sorted:
+
+        ======  ================================
+        `side`  returned index `i` satisfies
+        ======  ================================
+        left    ``self[i-1] < value <= self[i]``
+        right   ``self[i-1] <= value < self[i]``
+        ======  ================================
+
+        Parameters
+        ----------
+        value : array-like, list or scalar
+            Value(s) to insert into `self`.
+        side : {'left', 'right'}, optional
+            If 'left', the index of the first suitable location found is given.
+            If 'right', return the last such index.  If there is no suitable
+            index, return either 0 or N (where N is the length of `self`).
+        sorter : 1-D array-like, optional
+            Optional array of integer indices that sort array a into ascending
+            order. They are typically the result of argsort.
+
+        Returns
+        -------
+        array of ints or int
+            If value is array-like, array of insertion points.
+            If value is scalar, a single integer.
+
+        See Also
+        --------
+        numpy.searchsorted : Similar method from NumPy.
+
+        Examples
+        --------
+        >>> arr = pd.array([1, 2, 3, 5])
+        >>> arr.searchsorted([4])
+        array([3])
+        """
+        # Note: the base tests provided by pandas only test the basics.
+        # We do not test
+        # 1. Values outside the range of the `data_for_sorting` fixture
+        # 2. Values between the values in the `data_for_sorting` fixture
+        # 3. Missing values.
+        arr = self.astype(object)
+        if isinstance(value, ExtensionArray):
+            value = value.astype(object)
+        return arr.searchsorted(value, side=side, sorter=sorter)
 
-    @doc(ExtensionArray.shift)
     def shift(self, periods: int = 1, fill_value=None) -> Self:
+        """
+        Shift values by desired number.
+
+        Newly introduced missing values are filled with
+        ``self.dtype.na_value``.
+
+        Parameters
+        ----------
+        periods : int, default 1
+            The number of periods to shift. Negative values are allowed
+            for shifting backwards.
+
+        fill_value : object, optional
+            The scalar value to use for newly introduced missing values.
+            The default is ``self.dtype.na_value``.
+
+        Returns
+        -------
+        ExtensionArray
+            Shifted.
+
+        See Also
+        --------
+        api.extensions.ExtensionArray.transpose : Return a transposed view on
+            this array.
+        api.extensions.ExtensionArray.factorize : Encode the extension array as an
+            enumerated type.
+
+        Notes
+        -----
+        If ``self`` is empty or ``periods`` is 0, a copy of ``self`` is
+        returned.
+
+        If ``periods > len(self)``, then an array of size
+        len(self) is returned, with all values filled with
+        ``self.dtype.na_value``.
+
+        For 2-dimensional ExtensionArrays, we are always shifting along axis=0.
+
+        Examples
+        --------
+        >>> arr = pd.array([1, 2, 3])
+        >>> arr.shift(2)
+        <IntegerArray>
+        [<NA>, <NA>, 1]
+        Length: 3, dtype: Int64
+        """
         # NB: shift is always along axis=0
         axis = 0
         fill_value = self._validate_scalar(fill_value)
@@ -338,8 +463,44 @@ def _pad_or_backfill(
                 new_values = self
         return new_values
 
-    @doc(ExtensionArray.fillna)
     def fillna(self, value, limit: int | None = None, copy: bool = True) -> Self:
+        """
+        Fill NA/NaN values using the specified method.
+
+        Parameters
+        ----------
+        value : scalar, array-like
+            If a scalar value is passed it is used to fill all missing values.
+            Alternatively, an array-like "value" can be given. It's expected
+            that the array-like have the same length as 'self'.
+        limit : int, default None
+            The maximum number of entries where NA values will be filled.
+        copy : bool, default True
+            Whether to make a copy of the data before filling. If False, then
+            the original should be modified and no new memory should be allocated.
+            For ExtensionArray subclasses that cannot do this, it is at the
+            author's discretion whether to ignore "copy=False" or to raise.
+
+        Returns
+        -------
+        ExtensionArray
+            With NA/NaN filled.
+
+        See Also
+        --------
+        api.extensions.ExtensionArray.dropna : Return ExtensionArray without
+            NA values.
+        api.extensions.ExtensionArray.isna : A 1-D array indicating if
+            each value is missing.
+
+        Examples
+        --------
+        >>> arr = pd.array([np.nan, np.nan, 2, 3, np.nan, np.nan])
+        >>> arr.fillna(0)
+        <IntegerArray>
+        [0, 0, 2, 3, 0, 0]
+        Length: 6, dtype: Int64
+        """
         mask = self.isna()
         if limit is not None and limit < len(self):
             # mypy doesn't like that mask can be an EA which need not have `cumsum`