Merge pull request #272 from jcrist/topk_key

Fix topk to work with 0 for key
pytoolz · Aug 19, 2015 · d1e3041 · d1e3041
2 parents ee78566 + dd87e4f
commit d1e3041
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diff --git a/toolz/itertoolz.py b/toolz/itertoolz.py
@@ -879,7 +879,7 @@ def topk(k, seq, key=None):
     See also:
         heapq.nlargest
     """
-    if key and not callable(key):
+    if key is not None and not callable(key):
         key = getter(key)
     return tuple(heapq.nlargest(k, seq, key=key))
 

diff --git a/toolz/tests/test_itertoolz.py b/toolz/tests/test_itertoolz.py
@@ -461,6 +461,8 @@ def test_topk():
     assert topk(2, [{'a': 1, 'b': 10}, {'a': 2, 'b': 9},
                     {'a': 10, 'b': 1}, {'a': 9, 'b': 2}], key='b') == \
         ({'a': 1, 'b': 10}, {'a': 2, 'b': 9})
+    assert topk(2, [(0, 4), (1, 3), (2, 2), (3, 1), (4, 0)], 0) == \
+        ((4, 0), (3, 1))
 
 
 def test_topk_is_stable():