From fa4ac71dd6602347d80e4cdb71f3867fb63d3578 Mon Sep 17 00:00:00 2001 From: Guido van Rossum Date: Fri, 10 Jul 1998 17:37:30 +0000 Subject: Small changes to map() and filter(): (1) If a sequence S is shorter than len(S) indicated, don't fail -- just use the shorter size. (I.e, len(S) is just a hint.) (2) Implement the special case map(None, S) as list(S) -- it's faster. --- Python/bltinmodule.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c index 775c318..63531db 100644 --- a/Python/bltinmodule.c +++ b/Python/bltinmodule.c @@ -190,8 +190,6 @@ builtin_filter(self, args) int ok; if ((item = (*sqf->sq_item)(seq, i)) == NULL) { - if (i < len) - goto Fail_1; if (PyErr_ExceptionMatches(PyExc_IndexError)) { PyErr_Clear(); break; @@ -784,6 +782,11 @@ builtin_map(self, args) func = PyTuple_GetItem(args, 0); n--; + if (func == Py_None && n == 1) { + /* map(None, S) is the same as list(S). */ + return PySequence_List(PyTuple_GetItem(args, 1)); + } + if ((seqs = PyMem_NEW(sequence, n)) == NULL) { PyErr_NoMemory(); goto Fail_2; @@ -820,7 +823,6 @@ builtin_map(self, args) if ((result = (PyObject *) PyList_New(len)) == NULL) goto Fail_2; - /* XXX Special case map(None, single_list) could be more efficient */ for (i = 0; ; ++i) { PyObject *alist, *item=NULL, *value; int any = 0; @@ -840,8 +842,6 @@ builtin_map(self, args) else { item = (*sqp->sqf->sq_item)(sqp->seq, i); if (item == NULL) { - if (i < sqp->len) - goto Fail_0; if (PyErr_ExceptionMatches( PyExc_IndexError)) { @@ -897,6 +897,9 @@ builtin_map(self, args) } } + if (i < len && PyList_SetSlice(result, i, len, NULL) < 0) + goto Fail_1; + PyMem_DEL(seqs); return result; -- cgit v0.12