[Tutor] file io: reading an int32 at the end of a file?
bgailer at sbcglobal.net
Wed Jul 6 23:17:53 CEST 2005
At 01:12 PM 7/6/2005, Marcus Goldfish wrote:
>I have a file format that ends in a 4-byte (int32) number. I would
>like to read this value in python on a WinXP machine with something
>fname = 'somefile'
>f = open(fname, 'rb')
>offset = f.read()
>... but this doesn't seem to work. The value that Python returns is:
>but I know from similar code in Matlab that the correct sequence is:
> 64 25 1 0
>Can someone point out my error?
A file is a sequence of characters. That is what Python is showing you.
Since 3 of them are not "graphic characters" Python displays their
hexadecimal equivalents.. x19 translated to base 10 is 25. To ask Python to
(in essence) cast a character to an integer you use the ord function.
Ord('\x19') will give you integer 25.
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