From ba86fa9d5f24aa33f994d3b7a4bd31fdd8cf70e8 Mon Sep 17 00:00:00 2001 From: Raymond Hettinger Date: Sat, 21 Feb 2009 23:20:57 +0000 Subject: [PATCH] In Py3.x, a list comprehension is now faster than list(map(itemgetter(0), iterable)). --- Lib/heapq.py | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/Lib/heapq.py b/Lib/heapq.py index b3616312d91..19a457b10dd 100644 --- a/Lib/heapq.py +++ b/Lib/heapq.py @@ -130,7 +130,6 @@ __all__ = ['heappush', 'heappop', 'heapify', 'heapreplace', 'merge', 'nlargest', 'nsmallest', 'heappushpop'] from itertools import islice, repeat, count, tee, chain -from operator import itemgetter import bisect def heappush(heap, item): @@ -377,13 +376,13 @@ def nsmallest(n, iterable, key=None): if key is None: it = zip(iterable, count()) # decorate result = _nsmallest(n, it) - return list(map(itemgetter(0), result)) # undecorate + return [r[0] for r in result] # undecorate # General case, slowest method in1, in2 = tee(iterable) it = zip(map(key, in1), count(), in2) # decorate result = _nsmallest(n, it) - return list(map(itemgetter(2), result)) # undecorate + return [r[2] for r in result] # undecorate _nlargest = nlargest def nlargest(n, iterable, key=None): @@ -415,13 +414,13 @@ def nlargest(n, iterable, key=None): if key is None: it = zip(iterable, count(0,-1)) # decorate result = _nlargest(n, it) - return list(map(itemgetter(0), result)) # undecorate + return [r[0] for r in result] # undecorate # General case, slowest method in1, in2 = tee(iterable) it = zip(map(key, in1), count(0,-1), in2) # decorate result = _nlargest(n, it) - return list(map(itemgetter(2), result)) # undecorate + return [r[2] for r in result] # undecorate if __name__ == "__main__": # Simple sanity test