Issue 2274: Add heapq.heappushpop().
diff --git a/Lib/heapq.py b/Lib/heapq.py
index 39e3800..23f5fcb 100644
--- a/Lib/heapq.py
+++ b/Lib/heapq.py
@@ -127,7 +127,7 @@
"""
__all__ = ['heappush', 'heappop', 'heapify', 'heapreplace', 'merge',
- 'nlargest', 'nsmallest']
+ 'nlargest', 'nsmallest', 'heappushpop']
from itertools import islice, repeat, count, imap, izip, tee
from operator import itemgetter, neg
@@ -165,6 +165,13 @@
_siftup(heap, 0)
return returnitem
+def heappushpop(heap, item):
+ """Fast version of a heappush followed by a heappop."""
+ if heap and item > heap[0]:
+ item, heap[0] = heap[0], item
+ _siftup(heap, 0)
+ return item
+
def heapify(x):
"""Transform list into a heap, in-place, in O(len(heap)) time."""
n = len(x)
@@ -304,7 +311,7 @@
# If available, use C implementation
try:
- from _heapq import heappush, heappop, heapify, heapreplace, nlargest, nsmallest
+ from _heapq import heappush, heappop, heapify, heapreplace, nlargest, nsmallest, heappushpop
except ImportError:
pass