From ca2382e2375ed36e3443478bf2c849a647a366a0 Mon Sep 17 00:00:00 2001
From: Philipp Rudiger <P.Rudiger@ed.ac.uk>
Date: Thu, 15 Feb 2018 18:38:08 +0000
Subject: [PATCH] Handled empty values

---
 holoviews/core/data/interface.py |  2 ++
 holoviews/core/data/pandas.py    | 10 ++++++++++
 2 files changed, 12 insertions(+)

diff --git a/holoviews/core/data/interface.py b/holoviews/core/data/interface.py
index 377a196469..9adc3a5f4e 100644
--- a/holoviews/core/data/interface.py
+++ b/holoviews/core/data/interface.py
@@ -290,6 +290,8 @@ def range(cls, dataset, dimension):
                 return (np.nanmin(column), np.nanmax(column))
             except TypeError:
                 column = [v for v in util.python2sort(column) if v is not None]
+                if not len(column):
+                    return np.NaN, np.NaN
                 return column[0], column[-1]
 
     @classmethod
diff --git a/holoviews/core/data/pandas.py b/holoviews/core/data/pandas.py
index ddf7105898..a8599eef68 100644
--- a/holoviews/core/data/pandas.py
+++ b/holoviews/core/data/pandas.py
@@ -292,6 +292,16 @@ def dframe(cls, columns, dimensions):
             return columns.data.copy()
 
 
+    @classmethod
+    def array(cls, dataset, dimensions):
+        if not dimensions:
+            dimensions = dataset.dimensions(label='name')
+        else:
+            dimensions = [dataset.get_dimensions(d).name for d in dimensions]
+        inds = [dataset.data.columns.index(dim.name) for dim in dimensions]
+        return dataset.data.values[:, inds]
+
+
     @classmethod
     def iloc(cls, dataset, index):
         rows, cols = index