harijay wrote:
Hi I am very confused with the use of the struct module to read binary
data from a file.
( I have only worked with ascii files so far)
I have a file spec for a Data-logger (http://www.dataq.com/support/
techinfo/ff.htm)
I am collecting some voltage , time traces on one channel and they are
written to the binary file on a 32 bit windows machine
The file spec says that the number of header bytes in the data file
header is stored as a 16 bit eye "I" at bits 6-7
Now I want to get at that number. When I try format !h I get a
meaningful number
If f is my file handle opened with "rb" mode
f.seek(5)
(Integer,) = struct.unpack('!h',f.read(2))
(Integer,)
(9348,)
I am assuming that means that there are 9348 header bytes . Can
someone look at the format spec and tell me if I am on the right
track.
Also if a binary guru can point me in the direction of a single line
format pythonic way to get at the header that will be great
The number of header bytes is stored in bytes 6-7, so you need seek(6),
and the 16-bit value is little-endian as far as I can tell:
f.seek(6)
header_bytes, = struct.unpack('<h', f.read(2))
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