[Numpy-discussion] fromfile and tofile access with a tempfile.TemporaryFile()
Travis Oliphant
oliphant at ee.byu.edu
Tue Dec 12 17:26:44 EST 2006
Tim Hirzel wrote:
>Good thought Chris,
>Normal reading and writing does seem to work. ..
>But, my friend Daniel figured out a workaround when I asked to confirm
>this behavior on his windows setup (and it is does behave the same for
>him). The first clue was this:
>
> >>> f = tempfile.TemporaryFile()
> >>> type(f)
><type 'instance'>
> >>> g = open("temp","w+b")
> >>> type(g)
><type 'file'>
>
>so Daniel did a dir(f) and found the 'file' attribute
>
>so if you do (where 'a' is a numpy array)
> >>> a.tofile(f.file)
>It works!
>
>writing to the "file" attribute of the TemporaryFile, it works fine! So
>that's good, but still a little hinky. Especially since it works on
>linux...
>on a linux platform, what does type(tempfile.TemporaryFile()) return? I
>assume an <type 'instance'> as well...
>
>anways, so at least there is a quick repair for now. Good news is, I
>assume using 'f.file' would work on linux too in terms of having a
>single cross-platform solution.
>
>
There is no file attribute on Linux. On linux you get
>>> type(f)
<type 'file'>
So, you might have to do something like:
if not isinstance(f, file):
f = f.file
before passing f to the tofile method.
It seems to me that the temporary file mechanism on Windows is a little
odd.
-Travis
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