ENH: extract label from input data in plot

tacaswell · jankatins · commit 85d0e7431252 · 2015-08-31T12:06:32.000+02:00
If the input data has a `name` attribute and a label is in explicitly
passed in, use the name as the label that will be used in automatic
calls to `legend`.
diff --git a/lib/matplotlib/axes/_base.py b/lib/matplotlib/axes/_base.py
@@ -15,7 +15,7 @@
 import matplotlib
 
 from matplotlib import cbook
-from matplotlib.cbook import _string_to_bool
+from matplotlib.cbook import _string_to_bool, iterable, get_index_y, get_label
 from matplotlib import docstring
 import matplotlib.colors as mcolors
 import matplotlib.lines as mlines
@@ -349,6 +349,9 @@ def _plot_args(self, tup, kwargs):
             if v is not None:
                 kw[k] = v
 
+        if 'label' not in kwargs or kwargs['label'] is None:
+            kwargs['label'] = get_label(tup[-1])
+
         if len(tup) == 2:
             x = np.atleast_1d(tup[0])
             y = np.atleast_1d(tup[-1])
diff --git a/lib/matplotlib/cbook.py b/lib/matplotlib/cbook.py
@@ -2515,6 +2515,13 @@ def get_index_y(y):
         y = np.atleast_1d(y)
         return np.arange(y.shape[0], dtype=float), y
 
+
+def get_label(y):
+    try:
+        return y.name
+    except AttributeError:
+        return None
+
 # Numpy > 1.6.x deprecates putmask in favor of the new copyto.
 # So long as we support versions 1.6.x and less, we need the
 # following local version of putmask.  We choose to make a
