Add Elec2 API example

Author: jaime-cespedes-sisniega

frouros/datasets/real.py

@@ -11,18 +11,42 @@
 class Elec2(BaseDatasetDownload):
     """Elec2 dataset [harries1999splice]_.
 
+    :param file_path: file path for the downloaded file, defaults to None. If None, the file will be downloaded to a temporary file.
+    :type file_path: Optional[str]
+
+    :Note:
+    Dataset can be downloaded from the following sources (in order of preference):
+
+    - https://nextcloud.ifca.es/index.php/s/2coqgBEpa82boLS/download
+    - https://www.openml.org/data/download/2419/electricity-normalized.arff
+
     :References:
 
     .. [harries1999splice] Harries, Michael.
         "Splice-2 comparative evaluation: Electricity pricing." (1999).
-    """
 
-    def __init__(self, file_path: Optional[str] = None) -> None:
-        """Init method.
+    :Example:
 
-        :param file_path: file path for the downloaded file
-        :type file_path: Optional[str]
-        """
+    >>> from frouros.datasets.real import Elec2
+    >>> elec2 = Elec2()
+    >>> elec2.download()
+    INFO:frouros:Trying to download data from https://nextcloud.ifca.es/index.php/s/2coqgBEpa82boLS/download to /tmp/tmpro3ienx0
+    >>> dataset = elec2.load()
+    >>> dataset
+    array([(0.    , b'2', 0.      , 0.056443, 0.439155, 0.003467, 0.422915, 0.414912, b'UP'),
+       (0.    , b'2', 0.021277, 0.051699, 0.415055, 0.003467, 0.422915, 0.414912, b'UP'),
+       (0.    , b'2', 0.042553, 0.051489, 0.385004, 0.003467, 0.422915, 0.414912, b'UP'),
+       ...,
+       (0.9158, b'7', 0.957447, 0.043593, 0.34097 , 0.002983, 0.247799, 0.362281, b'DOWN'),
+       (0.9158, b'7', 0.978723, 0.066651, 0.329366, 0.00463 , 0.345417, 0.206579, b'UP'),
+       (0.9158, b'7', 1.      , 0.050679, 0.288753, 0.003542, 0.355256, 0.23114 , b'DOWN')],
+      dtype=[('date', '<f8'), ('day', 'S1'), ('period', '<f8'), ('nswprice', '<f8'), ('nswdemand', '<f8'), ('vicprice', '<f8'), ('vicdemand', '<f8'), ('transfer', '<f8'), ('class', 'S4')])
+    """  # noqa: E501  # pylint: disable=line-too-long
+
+    def __init__(  # noqa: D107
+        self,
+        file_path: Optional[str] = None,
+    ) -> None:
         super().__init__(
             url=[
                 "https://nextcloud.ifca.es/index.php/s/2coqgBEpa82boLS/download",