Terry J. Reedy <tjre...@udel.edu> added the comment: You are right, I misinterpreted the meaning of 's' without a count (and opened #11436 to clarify). However, for the fairly common case where a variable-length binary block is preceded by a 4 byte *binary* count, one can do something which is not too bad:
>>> block = b'lsfjdlksaj' >>> n=len(block) >>> struct.pack('I%ds'%n, n, block) b'\n\x00\x00\x00lsfjdlksaj' If leading blanks are acceptable for your example with count as ascii hex digits, one can do something that I admit is worse: >>> struct.pack('10s%ds2s'%n, ('%8x\r\n'%n).encode(), block, b'\r\n') b' a\r\nlsfjdlksaj\r\n' Of course, for either of these in isolation, I would probably only use .pack for the binary conversion and otherwise use '+' or b''.join(...). ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue3982> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com