[Numpy-discussion] reading big-endian uint16 into array on little-endian machine

greg whittier gregwh@gmail....
Thu Jun 17 09:29:54 CDT 2010

I have files (from an external source) that contain ~10 GB of
big-endian uint16's that I need to read into a series of arrays.  What
I'm doing now is

import numpy as np
import struct

fd = open('file.raw', 'rb')

for n in range(10000)
    count = 1024*1024
    a = np.array([struct.unpack('>H', fd.read(2)) for i in range(count)])
    # do something with a

It doesn't seem very efficient to call struct.unpack one element at a
time, but struct doesn't have an unpack_farray version like xdrlib
does.  I also thought of using the array module and .byteswap() but
the help says it only work on 4 and 8 byte arrays.

Any ideas?


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