[Numpy-discussion] major bug in fromstring, ascii mode

Charles R Harris charlesr.harris@gmail....
Sun Jan 27 16:43:41 CST 2008


On Jan 27, 2008 3:19 PM, Pauli Virtanen <pav@iki.fi> wrote:

>
> su, 2008-01-27 kello 13:48 -0700, Charles R Harris kirjoitti:
> [clip]
> >
> > I don't think the problem is scanf, at least not here. The following
> code snippet works fine for me.
> >
>
> Reading the code in arraytypes.inc.src and multiarraymodule.c, it
> appears that numpy is using strtol(str, &tailptr, 0) for the string to
> integer conversion. Calling strtol with BASE == 0 enables the automatic
> base detection from the prefix.
>
> However, as you say, scanf does not do this. Numpy appears to use fscanf
> when reading data from files, so there is a discrepancy here:
>
> >>> from numpy import fromfile, fromstring
> >>> f = open('test.dat', 'w')
> >>> f.write("20:09:21")
> >>> f.close()
>
> >>> fromfile('test.dat', dtype=int, sep=':')
> array([20,  9, 21])
> >>> fromstring('20:09:21', dtype=int, sep=':')
> array([20,  0])
>

I vote for fromstring working like fromfile.


>
> Also, the following result is quite strange, seems like a silent
> failure:
>
> >>> fromfile('test.dat', dtype=int)
> array([809119794, 825375289])
>

The default is to treat the file as containing binary data.

Chuck
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