Beginner: Data type conversion question

flagg ianand0204 at gmail.com
Fri Jan 16 18:02:08 CET 2009


On Jan 15, 11:35 pm, Terry Reedy <tjre... at udel.edu> wrote:
> flagg wrote:
> > I am still fairly new to python and programming in general.  My
> > question is regardingdataconversion, I am working on a script that
> > will edit dns zone files, one of the functions i wrote handles
> > updating the serial number.
> > Our zone files use the date as the first part of the serial and a two
> > digit integer as the last two.
>
> > i.e. 2009011501.  The next update would be 2009011502, etc
> > Here is the function I wrote, I am using dnspython for reading in zone
> > files as Zone "objects".  Because dnspython's built-in serial updater
> > will not work with how we format our serial's, I have to re-write it.
>
> > def checkSerial():
> >     """
> >     Checks the current 'date' portion of the serial number and
> >     checks the current 'counter'(the two digit number at the end of
> >     the serial number), then returns a complete new serial
> >     """
> >     currentDate =  time.strftime("%Y""%m""%d", time.localtime())
> >     for (name, ttl, rdata) in zone.iterate_rdatas(SOA):
> >         date = str(rdata.serial)[0:8]
> >         inc = str(rdata.serial)[8:10]
>
> If rdate.serial is already a string, as name would imply, the str() call
> is pointless.  If not, can you get inc as int more directly?
>
>
>
> >     if date == currentDate:
> >         int(inc) + 1
> >         print inc
> >         newInc = str(inc).zfill(2)
> >         serial = date + newInc
> >         print "date is the same"
> >         return serial
> >     elif date < currentDate:
> >         newInc = "01".zfill(2)
> >         serial = currentDate + newInc
> >         print "date is different"
> >         return serial
>
> > Through all of this I am doing a lot ofdatatypeconversion. string -
> >> integer, integer back to string, etc.  Is this an efficient way of
> > handling this?  I have to perform basic addition on the "inc"
> > variable, but also need to expose that value as a string.   What I
> > have above does work, but I can't help but think there is a more
> > efficient way. I guess I am not used todatatypes being converted so
> > easily.
>
> Other than that, you are perhaps worrying too much, even if code could
> be squeezed more.  The idea that every object knows how to convert
> itself to a string representation is basic to Python.
>
> tjr

Actually when i run a type(serial) on that variable it returns a
"long"  which i am not sure why dnspython uses a long variable to
store the serial.   But you could be right about me worrying to much.
The other languages I have dabbled in (java, perl) I don't remember
type conversion being as simple.   But again I am still new, so don't
quote me on that :)



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