DOC: update docstring of pandas.Series.add_prefix docstring (#20313)

Author: astrastefania

pandas/core/generic.py

@@ -2934,15 +2934,56 @@ def _update_inplace(self, result, verify_is_copy=True):
 
     def add_prefix(self, prefix):
         """
-        Concatenate prefix string with panel items names.
+        Prefix labels with string `prefix`.
+
+        For Series, the row labels are prefixed.
+        For DataFrame, the column labels are prefixed.
 
         Parameters
         ----------
-        prefix : string
+        prefix : str
+            The string to add before each label.
 
         Returns
         -------
-        with_prefix : type of caller
+        Series or DataFrame
+            New Series or DataFrame with updated labels.
+
+        See Also
+        --------
+        Series.add_suffix: Suffix labels with string `suffix`.
+
+        Examples
+        --------
+        >>> s = pd.Series([1, 2, 3, 4])
+        >>> s
+        0    1
+        1    2
+        2    3
+        3    4
+        dtype: int64
+
+        >>> s.add_prefix('item_')
+        item_0    1
+        item_1    2
+        item_2    3
+        item_3    4
+        dtype: int64
+
+        >>> df = pd.DataFrame({'A': [1, 2, 3, 4],  'B': [3, 4, 5, 6]})
+        >>> df
+           A  B
+        0  1  3
+        1  2  4
+        2  3  5
+        3  4  6
+
+        >>> df.add_prefix('col_')
+             col_A  col_B
+        0       1       3
+        1       2       4
+        2       3       5
+        3       4       6
         """
         new_data = self._data.add_prefix(prefix)
         return self._constructor(new_data).__finalize__(self)