ignore first column (poi) for zero- checks

tools/feature_format.py

@@ -40,6 +40,8 @@ def featureFormat( dictionary, features, remove_NaN=True, remove_all_zeroes=True
             all the features you seek are 0.0
         remove_any_zeroes=True will omit any data points for which
             any of the features you seek are 0.0
+        NOTE: first feature is assumed to be 'poi' and is not checked for
+            removal for zero or missing values.
     """
 
 
@@ -69,15 +71,15 @@ def featureFormat( dictionary, features, remove_NaN=True, remove_all_zeroes=True
         ### data points that are all zero, do that here
         if remove_all_zeroes:
             append = False
-            for item in tmp_list:
+            for item in tmp_list[1:]:
                 if item != 0 and item != "NaN":
                     append = True
                     break
         ### if any features for a given data point are zero
         ### and you want to remove data points with any zeroes,
         ### handle that here
         if remove_any_zeroes:
-            if 0 in tmp_list or "NaN" in tmp_list:
+            if 0 in tmp_list[1:] or "NaN" in tmp_list[1:]:
                 append = False
         ### Append the data point if flagged for addition.
         if append: