fix #874 : implemented Axis.min() and Axis.max() methods

alixdamman · alixdamman · commit b92cf7153cbc · 2021-03-01T14:24:15.000+01:00
diff --git a/doc/source/api.rst b/doc/source/api.rst
@@ -49,6 +49,8 @@ Searching
    Axis.startingwith
    Axis.endingwith
    Axis.matching
+   Axis.min
+   Axis.max
 
 Modifying/Selecting
 -------------------
diff --git a/doc/source/changes/version_0_33.rst.inc b/doc/source/changes/version_0_33.rst.inc
@@ -63,6 +63,8 @@ Miscellaneous improvements
 
 * implemented the :py:obj:`Array.allclose()` method (closes :issue:`871`).
 
+* implemented :py:obj:`Axis.min()` and :py:obj:`Axis.max()` methods (closes :issue:`874`).
+
 Fixes
 ^^^^^
 
diff --git a/larray/core/axis.py b/larray/core/axis.py
@@ -4,7 +4,7 @@
 import warnings
 from itertools import product
 
-from typing import Union
+from typing import Union, Any
 
 import numpy as np
 import pandas as pd
@@ -614,6 +614,60 @@ def equals(self, other):
         return isinstance(other, Axis) and self.name == other.name and self.iswildcard == other.iswildcard and \
             (len(self) == len(other) if self.iswildcard else np.array_equal(self.labels, other.labels))
 
+    def min(self) -> Any:
+        """
+        Get minimum of labels.
+
+        Returns
+        -------
+        label
+            Label with minimum value.
+
+        Warnings
+        --------
+        Fails on non-numeric labels.
+
+        Examples
+        --------
+        >>> time = Axis('time=1991..2020')
+        >>> time.min()
+        1991
+
+        >>> country = Axis('country=Belgium,France,Germany')
+        >>> country.min()
+        Traceback (most recent call last):
+        ...
+        TypeError: cannot perform reduce with flexible type
+        """
+        return np.nanmin(self.labels)
+
+    def max(self) -> Any:
+        """
+        Get maximum of labels.
+
+        Returns
+        -------
+        label
+            Label with maximum value.
+
+        Warnings
+        --------
+        Fails on non-numeric labels.
+
+        Examples
+        --------
+        >>> time = Axis('time=1991..2020')
+        >>> time.max()
+        2020
+
+        >>> country = Axis('country=Belgium,France,Germany')
+        >>> country.max()
+        Traceback (most recent call last):
+        ...
+        TypeError: cannot perform reduce with flexible type
+        """
+        return np.nanmax(self.labels)
+
     def matching(self, deprecated=None, pattern=None, regex=None):
         r"""
         Returns a group with all the labels matching the specified pattern or regular expression.
