Michael Yanowitz wrote: > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf > Of Simon Forman > Sent: Wednesday, July 26, 2006 2:56 PM > To: python-list@python.org > Subject: Re: Splitting a float into bytes: > > > Michael Yanowitz wrote: > > Hello: > > > > For some reason I can't figure out how to split > > a 4-byte (for instance) float number (such as 3.14159265359) > > into its 4-bytes so I can send it via a socket to another > > computer. > > For integers, it is easy, I can get the 4 bytes by anding like: > > byte1 = int_val & 0x000000FF > > byte2 = int_val & 0x0000FF00 > > byte3 = int_val & 0x00FF0000 > > byte4 = int_val & 0xFF000000 > > But if I try to do that with floats I get: > > >>> pi & 0xFF > > Traceback (most recent call last): > > File "<stdin>", line 1, in ? > > TypeError: unsupported operand type(s) for &: 'float' and 'int' > > > > Is there some easy way to get what the bytes of the float are? > > > > Thanks in advance: > > Michael Yanowitz > > The struct module. (It also works for ints. ;-) ) > > http://docs.python.org/lib/module-struct.html > > > HTH, > ~Simon > > Thanks, but maybe I am missing something. > If I use pack, doesn't it have to be unpacked at the other end > to make sense? The data will be picked up on some other computer > by some other application probably written in C or C++. Would > it have to be rewritten to unpack the data? > > Thanks in advance: > Michael Yanowitz
It says in the docs "This module performs conversions between Python values and C structs represented as Python strings." This means, to me, that the packed data will be in the format that C (and C++ I would assume) uses. You might have to mind the endian-ness if you're transferring data between different architectures, but struct includes format specifiers for this. Have fun, ~Simon -- http://mail.python.org/mailman/listinfo/python-list
