[Python-Dev] PEP 414 - Unicode Literals for Python 3 (original) (raw)

Serhiy Storchaka storchaka at gmail.com
Sun Feb 26 14:03:36 CET 2012

26.02.12 14:42, Armin Ronacher написав(ла):

On 2/26/12 12:35 PM, Serhiy Storchaka wrote:

Some microbenchmarks:

$ python -m timeit -n 10000 -r 100 -s "x = 123" "'foobarbaz%d' % x" 10000 loops, best of 100: 1.24 usec per loop $ python -m timeit -n 10000 -r 100 -s "x = 123" "str('foobarbaz%d') % x" 10000 loops, best of 100: 1.59 usec per loop $ python -m timeit -n 10000 -r 100 -s "x = 123" "str(u'foobarbaz%d') % x" 10000 loops, best of 100: 1.58 usec per loop $ python -m timeit -n 10000 -r 100 -s "x = 123; n = lambda s: s" "n('foobarbaz%d') % x" 10000 loops, best of 100: 1.41 usec per loop $ python -m timeit -n 10000 -r 100 -s "x = 123; s = 'foobarbaz%d'" "s % x" 10000 loops, best of 100: 1.22 usec per loop There are no significant overhead to use converters. That's because what you're benchmarking here more than anything is the overhead of eval() :-) See the benchmark linked in the PEP for one that measures the actual performance of the string literal / wrapper.

$ python -m timeit -n 10000 -r 100 "" 10000 loops, best of 100: 0.087 usec per loop

Overhead of eval is 5%.

Real code is not single string literal, every string literal occured together with a lot of code (getting and setting variables, attribute access, function calls, binary operators, unconditional and conditional jumps, etc), and total effect of using simple converter will be insignificant.

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