mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-07-24 11:44:31 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 8

operator.itemgetter() and operator.attrgetter() now support extraction

Browse source 
of multiple fields.  This provides direct support for sorting by
multiple keys.
This commit is contained in:
Raymond Hettinger 2005-03-09 16:38:48 +00:00
parent 6a3f4f7bc3
commit 984f9bb714
4 changed files with 118 additions and 23 deletions
Download patch file Download diff file Expand all files Collapse all files

86
Modules/operator.c
View file

@ -256,6 +256,7 @@ spam2(ge,__ge__, "ge(a, b) -- Same as a>=b.")
typedef struct {
PyObject_HEAD
int nitems;
PyObject *item;
} itemgetterobject;
@ -266,9 +267,14 @@ itemgetter_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
itemgetterobject *ig;
PyObject *item;
int nitems;
if (!PyArg_UnpackTuple(args, "itemgetter", 1, 1, &item))
return NULL;
nitems = PyTuple_GET_SIZE(args);
if (nitems <= 1) {
if (!PyArg_UnpackTuple(args, "itemgetter", 1, 1, &item))
return NULL;
} else
item = args;
/* create itemgetterobject structure */
ig = PyObject_GC_New(itemgetterobject, &itemgetter_type);
@ -277,6 +283,7 @@ itemgetter_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
Py_INCREF(item);
ig->item = item;
ig->nitems = nitems;
PyObject_GC_Track(ig);
return (PyObject *)ig;
@ -301,18 +308,40 @@ itemgetter_traverse(itemgetterobject *ig, visitproc visit, void *arg)
static PyObject *
itemgetter_call(itemgetterobject *ig, PyObject *args, PyObject *kw)
{
PyObject * obj;
PyObject *obj, *result;
int i, nitems=ig->nitems;
if (!PyArg_UnpackTuple(args, "itemgetter", 1, 1, &obj))
return NULL;
return PyObject_GetItem(obj, ig->item);
if (nitems == 1)
return PyObject_GetItem(obj, ig->item);
assert(PyTuple_Check(ig->item));
assert(PyTuple_GET_SIZE(ig->item) == nitems);
result = PyTuple_New(nitems);
if (result == NULL)
return NULL;
for (i=0 ; i < nitems ; i++) {
PyObject *item, *val;
item = PyTuple_GET_ITEM(ig->item, i);
val = PyObject_GetItem(obj, item);
if (val == NULL) {
Py_DECREF(result);
return NULL;
}
PyTuple_SET_ITEM(result, i, val);
}
return result;
}
PyDoc_STRVAR(itemgetter_doc,
"itemgetter(item) --> itemgetter object\n\
"itemgetter(item, ...) --> itemgetter object\n\
\n\
Return a callable object that fetches the given item from its operand.\n\
After, f=itemgetter(2), the call f(b) returns b[2].");
Return a callable object that fetches the given item(s) from its operand.\n\
After, f=itemgetter(2), the call f(r) returns r[2].\n\
After, g=itemgetter(2,5,3), the call g(r) returns (r[2], r[5], r[3])");
static PyTypeObject itemgetter_type = {
PyObject_HEAD_INIT(NULL)
@ -363,6 +392,7 @@ static PyTypeObject itemgetter_type = {
typedef struct {
PyObject_HEAD
int nattrs;
PyObject *attr;
} attrgetterobject;
@ -373,9 +403,14 @@ attrgetter_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
attrgetterobject *ag;
PyObject *attr;
int nattrs;
if (!PyArg_UnpackTuple(args, "attrgetter", 1, 1, &attr))
return NULL;
nattrs = PyTuple_GET_SIZE(args);
if (nattrs <= 1) {
if (!PyArg_UnpackTuple(args, "attrgetter", 1, 1, &attr))
return NULL;
} else
attr = args;
/* create attrgetterobject structure */
ag = PyObject_GC_New(attrgetterobject, &attrgetter_type);
@ -384,6 +419,7 @@ attrgetter_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
Py_INCREF(attr);
ag->attr = attr;
ag->nattrs = nattrs;
PyObject_GC_Track(ag);
return (PyObject *)ag;
@ -408,18 +444,40 @@ attrgetter_traverse(attrgetterobject *ag, visitproc visit, void *arg)
static PyObject *
attrgetter_call(attrgetterobject *ag, PyObject *args, PyObject *kw)
{
PyObject * obj;
PyObject *obj, *result;
int i, nattrs=ag->nattrs;
if (!PyArg_UnpackTuple(args, "attrgetter", 1, 1, &obj))
return NULL;
return PyObject_GetAttr(obj, ag->attr);
if (ag->nattrs == 1)
return PyObject_GetAttr(obj, ag->attr);
assert(PyTuple_Check(ag->attr));
assert(PyTuple_GET_SIZE(ag->attr) == nattrs);
result = PyTuple_New(nattrs);
if (result == NULL)
return NULL;
for (i=0 ; i < nattrs ; i++) {
PyObject *attr, *val;
attr = PyTuple_GET_ITEM(ag->attr, i);
val = PyObject_GetAttr(obj, attr);
if (val == NULL) {
Py_DECREF(result);
return NULL;
}
PyTuple_SET_ITEM(result, i, val);
}
return result;
}
PyDoc_STRVAR(attrgetter_doc,
"attrgetter(attr) --> attrgetter object\n\
"attrgetter(attr, ...) --> attrgetter object\n\
\n\
Return a callable object that fetches the given attribute from its operand.\n\
After, f=attrgetter('name'), the call f(b) returns b.name.");
Return a callable object that fetches the given attribute(s) from its operand.\n\
After, f=attrgetter('name'), the call f(r) returns r.name.\n\
After, g=attrgetter('name', 'date'), the call g(r) returns (r.name, r.date).");
static PyTypeObject attrgetter_type = {
PyObject_HEAD_INIT(NULL)