in c extension what is easiest way to build a (PyObject) list from an array of doubles?

[Christian Seberino]

In c extension what is easiest way to build a (PyObject) list from an
array of doubles?

I don't think I can do "return Py_BuildValue(...) to make a list from
an array can I???

How else can I build and return a list??

Thanks!

Chris+

 

[Paul Prescod]

In c extension what is easiest way to build a (PyObject) list from an
array of doubles?

No. Check out the array module.

Paul Prescod

 

[seberino]

Paul

Thanks. I agree array is great in Python for processing
homogenous lists but what about in **C code** if you must
return a Python list built from a C array?

How do you build a list/tuple/array/ from a C array of numbers?

Chris

No. Check out the array module.

Paul Prescod

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Phone: (619) 553-9973
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[Andrew MacIntyre]

How do you build a list/tuple/array/ from a C array of numbers?

The API docs are what you need to look at.

To create a tuple, call PyTuple_New().

For each element in your C array, build a Python object then use
PyTuple_SetItem() to insert it into the tuple.

 

[seberino]

Andrew

Thanks. I did it and it looks like it works too.

Chris

The API docs are what you need to look at.

To create a tuple, call PyTuple_New().

For each element in your C array, build a Python object then use
PyTuple_SetItem() to insert it into the tuple.

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_______________________________________

Christian Seberino, Ph.D.
SPAWAR Systems Center San Diego
Code 2872
49258 Mills Street, Room 158
San Diego, CA 92152-5385
U.S.A.

Phone: (619) 553-9973
Fax : (619) 553-6521
Email: (e-mail address removed)
_______________________________________

 

[Skip Montanaro]

Chris> In c extension what is easiest way to build a (PyObject) list
Chris> from an array of doubles?

Chris> I don't think I can do "return Py_BuildValue(...) to make a list
Chris> from an array can I???

If the length of the array is known when you write the code I think
something like this will work:

return Py_BuildValue("[dddd]", a[0], a[1], a[2], a[3]);

Chris> How else can I build and return a list??

Something like this (untested, no error checking):

int alen = sizeof(a)/sizeof(a[0]);
PyObject *list_of_floats = PyList_New(alen);
for (i = 0; i < alen; i++) {
PyList_SET_ITEM(list_of_floats, i, PyInt_FromLong(a));
}
return list_of_floats;

Skip