[Python-Dev] performance of {} versus dict(), de fmd(**kw): return kw trumps all ; -)

[Chris Withers]

On 14/11/2012 22:37, Chris Withers wrote:
> On 14/11/2012 10:11, martin at v.loewis.de wrote:
>> def xdict(**kwds):
>>    return kwds
>
> Hah, good call, this trumps both of the other options:
>
> $ python2.7 -m timeit -n 1000000 -r 5 -v
> "{'a':1,'b':2,'c':3,'d':4,'e':5,'f':6,'g':7}"
> raw times: 1.45 1.45 1.44 1.45 1.45
> 1000000 loops, best of 5: 1.44 usec per loop
> $ python2.6 -m timeit -n 1000000 -r 5 -v
> 'dict(a=1,b=2,c=3,d=4,e=5,f=6,g=7)'
> raw times: 2.37 2.36 2.36 2.37 2.37
> 1000000 loops, best of 5: 2.36 usec per loop$ python2.6 -m timeit -n
> 1000000 -r 5 -v 'def md(**kw): return kw; md(a=1,b=2,c=3,d=4,e=5,f=6,g=7)'
> raw times: 0.548 0.533 0.55 0.577 0.539
> 1000000 loops, best of 5: 0.533 usec per loop

Before anyone shoots me, yes, wrong python for two of them:

$ python2.7 -m timeit -n 1000000 -r 5 -v 
"{'a':1,'b':2,'c':3,'d':4,'e':5,'f':6,'g':7}"
raw times: 1.49 1.49 1.5 1.49 1.48
1000000 loops, best of 5: 1.48 usec per loop

$ python2.7 -m timeit -n 1000000 -r 5 -v 'dict(a=1,b=2,c=3,d=4,e=5,f=6,g=7)'
raw times: 2.35 2.36 2.41 2.42 2.35
1000000 loops, best of 5: 2.35 usec per loop

$ python2.7 -m timeit -n 1000000 -r 5 -v 'def md(**kw): return kw; 
md(a=1,b=2,c=3,d=4,e=5,f=6,g=7)'
raw times: 0.507 0.515 0.516 0.529 0.524
1000000 loops, best of 5: 0.507 usec per loop

Chris

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