Merge pull request Kozea#133 from gjvnq/master

Added new mode to box plot chart: "extremes"

pygal/config.py

@@ -320,6 +320,10 @@ class Config(CommonConfig):
         "ie: For hermite interpolation, you can set the cardinal tension with"
         "{'type': 'cardinal', 'c': .5}", int)
 
+    mode = Key(
+        None, str, "Value", "Sets the mode to be used. (Currently only supported on box plot)",
+        "May be %s" % ' or '.join(["1.5IQR", "extremes"]))
+
     order_min = Key(
         None, int, "Value", "Minimum order of scale, defaults to None")
 

pygal/graph/box.py

@@ -47,7 +47,10 @@ def _format(self):
 
         def format_maybe_quartile(x):
             if is_list_like(x):
-                return 'Q1: %s Q2: %s Q3: %s' % tuple(map(sup, x[1:4]))
+                if self.mode == "extremes":
+                    return 'Min: %s Q1: %s Q2: %s Q3: %s Max: %s' % tuple(map(sup, x))
+                else:
+                    return 'Q1: %s Q2: %s Q3: %s' % tuple(map(sup, x[1:4]))
             else:
                 return sup(x)
         return format_maybe_quartile
@@ -58,7 +61,7 @@ def _compute(self):
         within the rendering process
         """
         for serie in self.series:
-            serie.values = self._box_points(serie.values)
+            serie.values = self._box_points(serie.values, self.mode)
 
         if self._min:
             self._box.ymin = min(self._min, self.zero)
@@ -160,10 +163,15 @@ def _draw_box(self, parent_node, quartiles, box_index):
             sum(quartiles) / len(quartiles)))
 
     @staticmethod
-    def _box_points(values):
+    def _box_points(values, mode='1.5IQR'):
         """
-        Return a 5-tuple of Q1 - 1.5 * IQR, Q1, Median, Q3,
+        Default mode: (mode='1.5IQR' or unset)
+            Return a 5-tuple of Q1 - 1.5 * IQR, Q1, Median, Q3,
         and Q3 + 1.5 * IQR for a list of numeric values.
+        Extremes mode: (mode='extremes')
+            Return a 5-tuple of minimum, Q1, Median, Q3,
+        and maximum for a list of numeric values.
+
 
         The iterator values may include None values.
 
@@ -203,6 +211,10 @@ def median(seq):
                     q3 = 0.25 * s[3*m+1] + 0.75 * s[3*m+2]
 
             iqr = q3 - q1
-            q0 = q1 - 1.5 * iqr
-            q4 = q3 + 1.5 * iqr
+            if mode == 'extremes':
+                q0 = min(s)
+                q4 = max(s)
+            else:
+                q0 = q1 - 1.5 * iqr
+                q4 = q3 + 1.5 * iqr
             return q0, q1, q2, q3, q4

pygal/test/test_box.py

@@ -49,6 +49,35 @@ def test_quartiles():
     assert q3 == 4
     assert q4 == 4
 
+def test_quartiles_min_extremes():
+    a = [-2.0, 3.0, 4.0, 5.0, 8.0]  # odd test data
+    q0, q1, q2, q3, q4 = Box._box_points(a, mode='extremes')
+
+    assert q1 == 7.0 / 4.0
+    assert q2 == 4.0
+    assert q3 == 23 / 4.0
+    assert q0 == -2.0  # min
+    assert q4 == 8.0  # max
+
+    b = [1.0, 4.0, 6.0, 8.0]  # even test data
+    q0, q1, q2, q3, q4 = Box._box_points(b, mode='extremes')
+
+    assert q2 == 5.0
+
+    c = [2.0, None, 4.0, 6.0, None]  # odd with None elements
+    q0, q1, q2, q3, q4 = Box._box_points(c, mode='extremes')
+
+    assert q2 == 4.0
+
+    d = [4]
+    q0, q1, q2, q3, q4 = Box._box_points(d, mode='extremes')
+
+    assert q0 == 4
+    assert q1 == 4
+    assert q2 == 4
+    assert q3 == 4
+    assert q4 == 4
+
 
 def test_simple_box():
     box = ghostedBox()