Noobie: Open file -> read characters & multiply

WaterWalk toolmaster at 163.com
Tue Dec 26 20:38:56 EST 2006


WaterWalk wrote:
> WaterWalk wrote:
> > gonzlobo wrote:
> > > I've been using Python for a few days. It's such the perfect language
> > > for parsing data!
> > >
> > > I really like it so far, but I'm having a hard time reading a file,
> > > reading the first few hex characters & converting them to an integer.
> > > Once the characters are converted to an integer, I'd like to write the
> > > data to another file.
> > >
> > > Here's the code snipped to the bare minimum:
> > > ---
> > > # Open File
> > > AP_File= open("AP.txt", "r")
> > > decoded_File= open("decoded.txt", "w")
> > >
> > > # read & process data line by line
> > > for line in AP_File:
> > >    time = int(hex(line[0:8]), 16) * 0.0001     # this line is completely hosed!
> > >    decodedFile.write(time)
> > >
> > > #close files
> > > AP_File.close()
> > > decoded_File.close()
> > > ---
> > > AP.txt
> > > 000000d5 26 0600 80 00 ec 80 02 03 7d db 02 33
> > > 000000d5 26 0601 80 00 80 00 02 37 fe 54 01 09
> > > 000000d5 06 0602 80 00 e0 00 01 29 fe d2 69 99
> > > 000000d5 06 0603 80 00 e0 00 02 29 fe d2 6a 99
> > > 000000d5 26 0604 80 00 fe 54 02 09 80 00 01 5d
> > > 000000d5 06 0605 80 00 e0 00 02 15 fc 71 ca 0b
> > > 000000d5 4a 0610 81 00 86 00 02 26 12 00 02 a6
> > > 000000d5 4f 0611 00 00 00 50 00 00 00 00 07 00
> > > 000000d5 06 0612 80 00 e0 00 01 15 fc 71 c9 0b
> > > 000000d5 0a 0613 08 5c 04 88 08 98 00 00 00 00
> > > 000000d5 06 0614 80 00 e0 00 02 01 60 79 82 2b
> > > 000000d5 0a 0615 08 00 00 00 00 00 00 00 00 00
> > > 000000d5 26 0616 80 00 80 00 02 5d 04 22 3a 88
> > > (actual files are 250MB!)
> > >
> > > decodedTime.txt (should be)
> > > 0.0213 26 0600 80 00 ec 80 02 03 7d db 02 33
> > > ...
> > >
> > > My boss and I are trying to complete the same task (he figured out how
> > > to do it, but his code uses a while != "" loop and doesn't look
> > > pythony (it looks too 'c'). Not that there's anything wrong with that!
> > >
> > > Any help is really appreciated.
> >
> > Use the built-in int(). It has an optional argument "radix" which
> > specifies the base for the conversion. For example:
> > >>> int("0x0A", 16)
> > >>> 10
>
> Oh I forget that ">>>" will cause the line to be hidden by default. The
> example is:
> int("0x0A", 16)    # will return 10

I misunderstand the question, sorry for this.

Why not just split the line read since each number is separated by
space or tab.  After splitting there is a list of numbers, then convert
the first element and write the list into a file.




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