[Python-Dev] PEP: Adding data-type objects to Python (original) (raw)

Travis Oliphant oliphant.travis at ieee.org
Thu Nov 2 02:08:41 CET 2006

Paul Moore wrote:

Enough of the abstract. As a concrete example, suppose I have a (byte) string in my program containing some binary data - an ID3 header, or a TCP packet, or whatever. It doesn't really matter. Does your proposal offer anything to me in how I might manipulate that data (assuming I'm not using NumPy)? (I'm not insisting that it should, I'm just trying to understand the scope of the PEP).

What do you mean by "manipulate the data." The proposal for a data-format object would help you describe that data in a standard way and therefore share that data between several library that would be able to understand the data (because they all use and/or understand the default Python way to handle data-formats).

It would be up to the other packages to "manipulate" the data.

So, what you would be able to do is take your byte-string and create a buffer object which you could then share with other packages:

Example:

b = buffer(bytestr, format=data_format_object)

Now.

a = numpy.frombuffer(b) a['field1'] # prints data stored in the field named "field1"

etc.

Or.

cobj = ctypes.frombuffer(b)

Now, cobj is a ctypes object that is basically a "structure" that can

be passed # directly to your C-code.

Does this help?

-Travis

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