ENH: add value_counts as top level function in API, close #1392

Author: wesm

RELEASE.rst

@@ -81,6 +81,7 @@ pandas 0.8.0
   - Add new ``cut`` function (patterned after R) for discretizing data into
     equal range-length bins or arbitrary breaks of your choosing (#415)
   - Add new ``qcut`` for cutting with quantiles (#1378)
+  - Add ``value_counts`` top level array method (#1392)
   - Added Andrews curves plot tupe (#1325)
   - Add support for tox and Travis CI (#1382)
 

pandas/core/algorithms.py

@@ -141,6 +141,14 @@ def value_counts(values, sort=True, ascending=False):
     """
     Compute a histogram of the counts of non-null values
 
+    Parameters
+    ----------
+    values : ndarray (1-d)
+    sort : boolean, default True
+        Sort by values
+    ascending : boolean, default False
+        Sort in ascending order
+
     Returns
     -------
     value_counts : Series

pandas/core/api.py

@@ -3,7 +3,7 @@
 
 import numpy as np
 
-from pandas.core.algorithms import factorize, match, unique
+from pandas.core.algorithms import factorize, match, unique, value_counts
 
 from pandas.core.common import isnull, notnull, save, load
 from pandas.core.factor import Factor