Fix convert_to_string method

dstansby · dstansby · commit aa0e899ff12c · 2016-11-21T15:03:31.000Z
diff --git a/lib/matplotlib/category.py b/lib/matplotlib/category.py
@@ -61,7 +61,7 @@ def __init__(self, seq):
 
 
 def convert_to_string(value):
-    return np.array(value, dtype=np.unicode)
+    return np.asarray(value, dtype=str)[np.newaxis][0]
 
 
 class UnitData(object):
