DOC: Fixing EX01 - Added examples (#54267)

* Example ExtensionArray._formatter * Added if boxed...

Author: DeaMariaLeon

ci/code_checks.sh

@@ -85,7 +85,6 @@ if [[ -z "$CHECK" || "$CHECK" == "docstrings" ]]; then
  pandas.api.extensions.ExtensionDtype \
  pandas.api.extensions.ExtensionArray \
  pandas.arrays.NumpyExtensionArray \
- pandas.api.extensions.ExtensionArray._formatter \
  pandas.api.extensions.ExtensionArray._from_factorized \
  pandas.api.extensions.ExtensionArray._from_sequence \
  pandas.api.extensions.ExtensionArray._from_sequence_of_strings \

pandas/core/arrays/base.py

@@ -1527,6 +1527,16 @@ def _formatter(self, boxed: bool = False) -> Callable[[Any], str | None]:
  returns a string. By default, :func:`repr` is used
  when ``boxed=False`` and :func:`str` is used when
  ``boxed=True``.
+
+ Examples
+ --------
+ >>> class MyExtensionArray(pd.arrays.NumpyExtensionArray):
+ ... def _formatter(self, boxed=False):
+ ... return lambda x: '*' + str(x) + '*' if boxed else repr(x) + '*'
+ >>> MyExtensionArray(np.array([1, 2, 3, 4]))
+ <MyExtensionArray>
+ [1*, 2*, 3*, 4*]
+ Length: 4, dtype: int64
  """
  if boxed:
  return str