Hi all, I've got some code which basically does : f = open (path, 'rb') header = f.read (some_length) data = np.fromfile (f, dtype= some_type, count=-1) In order to process compressed files, I switched the open sequence to : if (plain): f = open (path, 'rb') else: f = gzip.open (path, 'rb') Then, the header reading is OK, since the gzip.file class has a "read " method : hdr = f.read (some_length) But I've got problems with np.fromfile, which says : IOError: first argument must be an open file I guess that fromfile() uses methods other than file.read(), while GzipFile does not simulates all the methods of a file object (readinto() and truncate() are listed the doc), so making fromfile() work with compressed file may not be straightforward. I had a try at StringIO() : data = np.fromfile (StringIO.StringIO(f.read()), dtype= some_type, count=-1) but it doesn't work better. So, I've got two questions : - Could numpy.fromfile() work with gzip-compressed files, as some other file functions do ? - I'm thinking of using something like np.array(f.read(), dtype=some_type). Any better solution ? With such a simple solution, maybe my error was to try to use fromfile() at the beginning ? Bruno.