Merge pull request #456 from plotly/fix-empty-generator-in-py3-trisurf

In python 3 `map` is a generator, `list()` it!

Author: Kully

plotly/tools.py

@@ -1562,7 +1562,7 @@ def _trisurf(x, y, z, simplices, colormap=None,
         points3D = np.vstack((x, y, z)).T
 
         # vertices of the surface triangles
-        tri_vertices = map(lambda index: points3D[index], simplices)
+        tri_vertices = list(map(lambda index: points3D[index], simplices))
         # mean values of z-coordinates of triangle vertices
         zmean = [np.mean(tri[:, 2]) for tri in tri_vertices]
         min_zmean = np.min(zmean)