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| author | Raymond Hettinger <python@rcn.com> | 2004-06-20 09:07:53 (GMT) |
|---|---|---|
| committer | Raymond Hettinger <python@rcn.com> | 2004-06-20 09:07:53 (GMT) |
| commit | 28224f897a1849dd616ad82538bdda45f3351d42 (patch) | |
| tree | 996268137e0f51ca92d0d5e93a90fae6c482d67f | |
| parent | 1761a7cc8b3fffb7c04d81609c705f353eef14a7 (diff) | |
| download | cpython-28224f897a1849dd616ad82538bdda45f3351d42.zip cpython-28224f897a1849dd616ad82538bdda45f3351d42.tar.gz cpython-28224f897a1849dd616ad82538bdda45f3351d42.tar.bz2 | |
Improve the documented advice on how to best use heapq.heapreplace().
| -rw-r--r-- | Doc/lib/libheapq.tex | 6 | ||||
| -rw-r--r-- | Lib/heapq.py | 4 | ||||
| -rw-r--r-- | Modules/_heapqmodule.c | 3 |
3 files changed, 10 insertions, 3 deletions
diff --git a/Doc/lib/libheapq.tex b/Doc/lib/libheapq.tex index ffcafcd..edacf79 100644 --- a/Doc/lib/libheapq.tex +++ b/Doc/lib/libheapq.tex @@ -59,7 +59,11 @@ If the heap is empty, \exception{IndexError} is raised. This is more efficient than \function{heappop()} followed by \function{heappush()}, and can be more appropriate when using a fixed-size heap. Note that the value returned may be larger -than \var{item}! That constrains reasonable uses of this routine. +than \var{item}! That constrains reasonable uses of this routine +unless written as part of a larger expression: +\begin{verbatim} + result = item <= heap[0] and item or heapreplace(heap, item) +\end{verbatim} \end{funcdesc} Example of use: diff --git a/Lib/heapq.py b/Lib/heapq.py index 09f996a..9fb4e70 100644 --- a/Lib/heapq.py +++ b/Lib/heapq.py @@ -154,7 +154,9 @@ def heapreplace(heap, item): This is more efficient than heappop() followed by heappush(), and can be more appropriate when using a fixed-size heap. Note that the value returned may be larger than item! That constrains reasonable uses of - this routine. + this routine unless written as part of a larger expression: + + result = item <= heap[0] and item or heapreplace(heap, item) """ returnitem = heap[0] # raises appropriate IndexError if heap is empty heap[0] = item diff --git a/Modules/_heapqmodule.c b/Modules/_heapqmodule.c index 21df796..13e6a3d 100644 --- a/Modules/_heapqmodule.c +++ b/Modules/_heapqmodule.c @@ -186,7 +186,8 @@ PyDoc_STRVAR(heapreplace_doc, This is more efficient than heappop() followed by heappush(), and can be\n\ more appropriate when using a fixed-size heap. Note that the value\n\ returned may be larger than item! That constrains reasonable uses of\n\ -this routine.\n"); +this routine unless written as part of a larger expression:\n\n\ + result = item <= heap[0] and item or heapreplace(heap, item)\n"); static PyObject * heapify(PyObject *self, PyObject *heap) |