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Performance when converting integer to byte representation in python

To be specific, I need to convert an integer, say 9999, to bytes, b'9999'in python 2.6 to python 3.x

In python 2.x I do

b'%s'%n

and in python 3.x

('%s'%n).encode()

Performance in python 2.6

>>> from timeit import Timer
>>> Timer('b"%s"%n','n=9999').timeit()
0.24728001750963813

Performance in python 3.2

>>> from timeit import Timer
>>> Timer('("%s"%n).encode()','n=9999').timeit()
0.534475012767416

Assuming my tests are set up correctly, this is a heavy punishment in python 3.x.

Is there a way to improve performance to close the gap with 2.6 / 2.7?

Perhaps via cython route?

This is the generator function I'm trying to optimize. It is called again and again when it argsis a list of strings, bytes or numbers:

def pack_gen(self, args, encoding='utf-8'):
    crlf = b'\r\n'
    yield ('*%s\r\n'%len(args)).encode(encoding)
    for value in args:
        if not isinstance(value, bytes):
            value = ('%s'%value).encode(encoding)
        yield ('$%s\r\n'%len(value)).encode(encoding)
        yield value
        yield crlf

The function is called this way.

b''.join(pack_gen(args))
+3
1

, repr() Python 3.2:

>>> Timer('repr(n).encode()','n=9999').timeit()
0.32432007789611816
>>> Timer('("%s" % n).encode()','n=9999').timeit()
0.44790005683898926

, , , "%s" % n.

Python 3.3.0a3, , PEP393 , , 3,2:

>>> Timer('repr(n).encode()','n=9999').timeit()
0.35951611599921307
>>> Timer('("%s"%n).encode()','n=9999').timeit()
0.4658188759985933

, :

>>> Timer('str(n).encode()','n=9999').timeit()
0.49958825100111426

, ( , Python str() repr() ). , , , , cython . , , .

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