Issue 2186 and 2187. Move filter from itertools to builtins.

Doc/library/itertools.rst

@@ -234,21 +234,6 @@ loops that truncate the stream.
                   self.currkey = self.keyfunc(self.currvalue)
 
 
-.. function:: ifilter(predicate, iterable)
-
-   Make an iterator that filters elements from iterable returning only those for
-   which the predicate is ``True``. If *predicate* is ``None``, return the items
-   that are true.  This function is the same as the built-in :func:`filter`
-   function.  Equivalent to::
-
-      def ifilter(predicate, iterable):
-          if predicate is None:
-              predicate = bool
-          for x in iterable:
-              if predicate(x):
-                  yield x
-
-
 .. function:: ifilterfalse(predicate, iterable)
 
    Make an iterator that filters elements from iterable returning only those for
@@ -606,13 +591,13 @@ which incur interpreter overhead. ::
 
    def any(seq, pred=None):
        "Returns True if pred(x) is true for at least one element in the iterable"
-       for elem in ifilter(pred, seq):
+       for elem in filter(pred, seq):
            return True
        return False
 
    def no(seq, pred=None):
        "Returns True if pred(x) is false for every element in the iterable"
-       for elem in ifilter(pred, seq):
+       for elem in filter(pred, seq):
            return False
        return True
 

Lib/filecmp.py

@@ -12,7 +12,7 @@ Functions:
 import os
 import stat
 import warnings
-from itertools import ifilter, ifilterfalse, imap, izip
+from itertools import ifilterfalse, imap, izip
 
 __all__ = ["cmp","dircmp","cmpfiles"]
 
@@ -132,7 +132,7 @@ class dircmp:
     def phase1(self): # Compute common names
         a = dict(izip(imap(os.path.normcase, self.left_list), self.left_list))
         b = dict(izip(imap(os.path.normcase, self.right_list), self.right_list))
-        self.common = list(map(a.__getitem__, ifilter(b.__contains__, a)))
+        self.common = list(map(a.__getitem__, filter(b.__contains__, a)))
         self.left_only = list(map(a.__getitem__, ifilterfalse(b.__contains__, a)))
         self.right_only = list(map(b.__getitem__, ifilterfalse(a.__contains__, b)))
 

Lib/test/test_itertools.py

@@ -8,6 +8,7 @@ import random
 from functools import reduce
 maxsize = test_support.MAX_Py_ssize_t
 minsize = -maxsize-1
+ifilter = filter
 
 def lzip(*args):
     return list(zip(*args))

Modules/itertoolsmodule.c

@@ -2208,149 +2208,6 @@ static PyTypeObject combinations_type = {
 };
 
 
-/* ifilter object ************************************************************/
-
-typedef struct {
-	PyObject_HEAD
-	PyObject *func;
-	PyObject *it;
-} ifilterobject;
-
-static PyTypeObject ifilter_type;
-
-static PyObject *
-ifilter_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
-{
-	PyObject *func, *seq;
-	PyObject *it;
-	ifilterobject *lz;
-
-	if (type == &ifilter_type && !_PyArg_NoKeywords("ifilter()", kwds))
-		return NULL;
-
-	if (!PyArg_UnpackTuple(args, "ifilter", 2, 2, &func, &seq))
-		return NULL;
-
-	/* Get iterator. */
-	it = PyObject_GetIter(seq);
-	if (it == NULL)
-		return NULL;
-
-	/* create ifilterobject structure */
-	lz = (ifilterobject *)type->tp_alloc(type, 0);
-	if (lz == NULL) {
-		Py_DECREF(it);
-		return NULL;
-	}
-	Py_INCREF(func);
-	lz->func = func;
-	lz->it = it;
-
-	return (PyObject *)lz;
-}
-
-static void
-ifilter_dealloc(ifilterobject *lz)
-{
-	PyObject_GC_UnTrack(lz);
-	Py_XDECREF(lz->func);
-	Py_XDECREF(lz->it);
-	Py_TYPE(lz)->tp_free(lz);
-}
-
-static int
-ifilter_traverse(ifilterobject *lz, visitproc visit, void *arg)
-{
-	Py_VISIT(lz->it);
-	Py_VISIT(lz->func);
-	return 0;
-}
-
-static PyObject *
-ifilter_next(ifilterobject *lz)
-{
-	PyObject *item;
-	PyObject *it = lz->it;
-	long ok;
-	PyObject *(*iternext)(PyObject *);
-
-	assert(PyIter_Check(it));
-	iternext = *Py_TYPE(it)->tp_iternext;
-	for (;;) {
-		item = iternext(it);
-		if (item == NULL)
-			return NULL;
-
-		if (lz->func == Py_None || lz->func == (PyObject *)&PyBool_Type) {
-			ok = PyObject_IsTrue(item);
-		} else {
-			PyObject *good;
-			good = PyObject_CallFunctionObjArgs(lz->func,
-							    item, NULL);
-			if (good == NULL) {
-				Py_DECREF(item);
-				return NULL;
-			}
-			ok = PyObject_IsTrue(good);
-			Py_DECREF(good);
-		}
-		if (ok)
-			return item;
-		Py_DECREF(item);
-	}
-}
-
-PyDoc_STRVAR(ifilter_doc,
-"ifilter(function or None, sequence) --> ifilter object\n\
-\n\
-Return those items of sequence for which function(item) is true.\n\
-If function is None, return the items that are true.");
-
-static PyTypeObject ifilter_type = {
-	PyVarObject_HEAD_INIT(NULL, 0)
-	"itertools.ifilter",		/* tp_name */
-	sizeof(ifilterobject),		/* tp_basicsize */
-	0,				/* tp_itemsize */
-	/* methods */
-	(destructor)ifilter_dealloc,	/* tp_dealloc */
-	0,				/* tp_print */
-	0,				/* tp_getattr */
-	0,				/* tp_setattr */
-	0,				/* tp_compare */
-	0,				/* tp_repr */
-	0,				/* tp_as_number */
-	0,				/* tp_as_sequence */
-	0,				/* tp_as_mapping */
-	0,				/* tp_hash */
-	0,				/* tp_call */
-	0,				/* tp_str */
-	PyObject_GenericGetAttr,	/* tp_getattro */
-	0,				/* tp_setattro */
-	0,				/* tp_as_buffer */
-	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
-		Py_TPFLAGS_BASETYPE,	/* tp_flags */
-	ifilter_doc,			/* tp_doc */
-	(traverseproc)ifilter_traverse,	/* tp_traverse */
-	0,				/* tp_clear */
-	0,				/* tp_richcompare */
-	0,				/* tp_weaklistoffset */
-	PyObject_SelfIter,		/* tp_iter */
-	(iternextfunc)ifilter_next,	/* tp_iternext */
-	0,				/* tp_methods */
-	0,				/* tp_members */
-	0,				/* tp_getset */
-	0,				/* tp_base */
-	0,				/* tp_dict */
-	0,				/* tp_descr_get */
-	0,				/* tp_descr_set */
-	0,				/* tp_dictoffset */
-	0,				/* tp_init */
-	0,				/* tp_alloc */
-	ifilter_new,			/* tp_new */
-	PyObject_GC_Del,		/* tp_free */
-};
-
-
 /* ifilterfalse object ************************************************************/
 
 typedef struct {
@@ -3208,7 +3065,6 @@ repeat(elem [,n]) --> elem, elem, elem, ... endlessly or up to n times\n\
 Iterators terminating on the shortest input sequence:\n\
 izip(p, q, ...) --> (p[0], q[0]), (p[1], q[1]), ... \n\
 izip_longest(p, q, ...) --> (p[0], q[0]), (p[1], q[1]), ... \n\
-ifilter(pred, seq) --> elements of seq where pred(elem) is True\n\
 ifilterfalse(pred, seq) --> elements of seq where pred(elem) is False\n\
 islice(seq, [start,] stop [, step]) --> elements from\n\
        seq[start:stop:step]\n\
@@ -3242,7 +3098,6 @@ inititertools(void)
 		&starmap_type,
 		&imap_type,
 		&chain_type,
-		&ifilter_type,
 		&ifilterfalse_type,
 		&count_type,
 		&izip_type,

Python/bltinmodule.c

@@ -277,29 +277,146 @@ PyDoc_STRVAR(bin_doc,
 Return the binary representation of an integer or long integer.");
 
 
+typedef struct {
+	PyObject_HEAD
+	PyObject *func;
+	PyObject *it;
+} filterobject;
+
+PyTypeObject PyFilter_Type;
+
 static PyObject *
-builtin_filter(PyObject *self, PyObject *args)
+filter_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
 {
-	PyObject *itertools, *ifilter, *result;
-	itertools = PyImport_ImportModuleNoBlock("itertools");
-	if (itertools == NULL)
+	PyObject *func, *seq;
+	PyObject *it;
+	filterobject *lz;
+
+	if (type == &PyFilter_Type && !_PyArg_NoKeywords("filter()", kwds))
 		return NULL;
-	ifilter = PyObject_GetAttrString(itertools, "ifilter");
-	Py_DECREF(itertools);
-	if (ifilter == NULL)
+
+	if (!PyArg_UnpackTuple(args, "filter", 2, 2, &func, &seq))
 		return NULL;
-	result = PyObject_Call(ifilter, args, NULL);
-	Py_DECREF(ifilter);
-	return result;
+
+	/* Get iterator. */
+	it = PyObject_GetIter(seq);
+	if (it == NULL)
+		return NULL;
+
+	/* create filterobject structure */
+	lz = (filterobject *)type->tp_alloc(type, 0);
+	if (lz == NULL) {
+		Py_DECREF(it);
+		return NULL;
+	}
+	Py_INCREF(func);
+	lz->func = func;
+	lz->it = it;
+
+	return (PyObject *)lz;
+}
+
+static void
+filter_dealloc(filterobject *lz)
+{
+	PyObject_GC_UnTrack(lz);
+	Py_XDECREF(lz->func);
+	Py_XDECREF(lz->it);
+	Py_TYPE(lz)->tp_free(lz);
+}
+
+static int
+filter_traverse(filterobject *lz, visitproc visit, void *arg)
+{
+	Py_VISIT(lz->it);
+	Py_VISIT(lz->func);
+	return 0;
+}
+
+static PyObject *
+filter_next(filterobject *lz)
+{
+	PyObject *item;
+	PyObject *it = lz->it;
+	long ok;
+	PyObject *(*iternext)(PyObject *);
+
+	assert(PyIter_Check(it));
+	iternext = *Py_TYPE(it)->tp_iternext;
+	for (;;) {
+		item = iternext(it);
+		if (item == NULL)
+			return NULL;
+
+		if (lz->func == Py_None || lz->func == (PyObject *)&PyBool_Type) {
+			ok = PyObject_IsTrue(item);
+		} else {
+			PyObject *good;
+			good = PyObject_CallFunctionObjArgs(lz->func,
+							    item, NULL);
+			if (good == NULL) {
+				Py_DECREF(item);
+				return NULL;
+			}
+			ok = PyObject_IsTrue(good);
+			Py_DECREF(good);
+		}
+		if (ok)
+			return item;
+		Py_DECREF(item);
+	}
 }
 
 PyDoc_STRVAR(filter_doc,
-"filter(predicate, iterable) -> iterator\n\
+"filter(function or None, sequence) --> filter object\n\
 \n\
-Return an iterator yielding only those elements of the input iterable\n\
-for which the predicate (a Boolean function) returns true.\n\
-If the predicate is None, 'lambda x: bool(x)' is assumed.\n\
-(This is identical to itertools.ifilter().)");
+Return an iterator yielding those items of sequence for which function(item)\n\
+is true. If function is None, return the items that are true.");
+
+PyTypeObject PyFilter_Type = {
+	PyVarObject_HEAD_INIT(&PyType_Type, 0)
+	"filter",			/* tp_name */
+	sizeof(filterobject),		/* tp_basicsize */
+	0,				/* tp_itemsize */
+	/* methods */
+	(destructor)filter_dealloc,	/* tp_dealloc */
+	0,				/* tp_print */
+	0,				/* tp_getattr */
+	0,				/* tp_setattr */
+	0,				/* tp_compare */
+	0,				/* tp_repr */
+	0,				/* tp_as_number */
+	0,				/* tp_as_sequence */
+	0,				/* tp_as_mapping */
+	0,				/* tp_hash */
+	0,				/* tp_call */
+	0,				/* tp_str */
+	PyObject_GenericGetAttr,	/* tp_getattro */
+	0,				/* tp_setattro */
+	0,				/* tp_as_buffer */
+	Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC |
+		Py_TPFLAGS_BASETYPE,	/* tp_flags */
+	filter_doc,			/* tp_doc */
+	(traverseproc)filter_traverse,	/* tp_traverse */
+	0,				/* tp_clear */
+	0,				/* tp_richcompare */
+	0,				/* tp_weaklistoffset */
+	PyObject_SelfIter,		/* tp_iter */
+	(iternextfunc)filter_next,	/* tp_iternext */
+	0,				/* tp_methods */
+	0,				/* tp_members */
+	0,				/* tp_getset */
+	0,				/* tp_base */
+	0,				/* tp_dict */
+	0,				/* tp_descr_get */
+	0,				/* tp_descr_set */
+	0,				/* tp_dictoffset */
+	0,				/* tp_init */
+	PyType_GenericAlloc,		/* tp_alloc */
+	filter_new,			/* tp_new */
+	PyObject_GC_Del,		/* tp_free */
+};
+
 
 static PyObject *
 builtin_format(PyObject *self, PyObject *args)
@@ -1763,7 +1880,6 @@ static PyMethodDef builtin_methods[] = {
  	{"divmod",	builtin_divmod,     METH_VARARGS, divmod_doc},
  	{"eval",	builtin_eval,       METH_VARARGS, eval_doc},
 	{"exec",        builtin_exec,       METH_VARARGS, exec_doc},
- 	{"filter",	builtin_filter,     METH_VARARGS, filter_doc},
  	{"format",	builtin_format,     METH_VARARGS, format_doc},
  	{"getattr",	builtin_getattr,    METH_VARARGS, getattr_doc},
  	{"globals",	(PyCFunction)builtin_globals,    METH_NOARGS, globals_doc},
@@ -1843,6 +1959,7 @@ _PyBuiltin_Init(void)
 #endif
 	SETBUILTIN("dict",		&PyDict_Type);
  	SETBUILTIN("enumerate",		&PyEnum_Type);
+ 	SETBUILTIN("filter",		&PyFilter_Type);
 	SETBUILTIN("float",		&PyFloat_Type);
 	SETBUILTIN("frozenset",		&PyFrozenSet_Type);
 	SETBUILTIN("property",		&PyProperty_Type);