Python 3 bytes formatting

And as of 3.5 % formatting will work for bytes, too!

Another way would be:

"{0}, {1}, {2}".format(1, 2, 3).encode()

Tested on IPython 1.1.0 & Python 3.2.3

python python-3.x string-formatting

Interestingly .format() doesn't appear to be supported for byte-sequences; as you have demonstrated.

You could use .join() as suggested here: http://bugs.python.org/issue3982

b", ".join([b'1', b'2', b'3'])

There is a speed advantage associated with .join() over using .format() shown by the BDFL himself: http://bugs.python.org/msg180449

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