[Tutor] How to write list to file

[Danny Yoo]

On Wed, 28 Jan 2004, Vicki Stanfield wrote:

> > I have the following code:
> >
> > print bytearray[0:bytetotal]
> > outfile.write("[")
> > for byte in bytearray[0:bytetotal]:
> >     outfile.write(byte)
> > outfile.write("]")
> >
> > The print statement prints this:
> >
> > ['F', '8', '\t']
> >
> > but the outfile has only this:
> >
> > [40	]
> >
> > I think the problem is that the program is trying to write [40 46 30 38
> \t], but for some reason stops at the 40. Why would the different way of
> writing cause this behavior?
> >
> Actually what I was thinking doesn't make sense. I know that the F is a
> 46 and the 8 is a 38 in hex. I am not sure where the 40 comes from.



Hi Vicki,

I'm not quite sure I understand quite yet this problem.  *grin*



But I'm guessing that '40\t' is meant to be interpreted as the characters
'4', '0', and '\t', but not as the number '40' followed by a tab.


Assuming that 'bytetotal' is 3, the three characters that you're writing:

    ['F', '8', '\t']

should correspond to the three bytes that you see in your file (plus the
two from the brackets).



Before we try figure out any more: is that code snippet the only part of
your program, or do you do some additional writing to file either before
or after this snippet?  What I don't get quite yet is how you're getting
'40\t' from the outfile:


> > but the outfile has only this:
> >
> > [40	]


There's something slightly irrational here, and I can't help but feel
we're not seeing something obvious.  *grin*


Given that the array contained ['F', '8', '\t'], after the loop, you
should be seeing

###
[F8	]
###

in your file.  Are you doing any file seek()ing after this snippet?  And
have you made sure to explicitely close() the outfile?


Good luck to you!