.format vs. %

[Neil Cerutti]

On 2012-01-03, Stefan Krah <stefan-usenet at bytereef.org> wrote:
> Neil Cerutti <neilc at norwich.edu> wrote:
>> > In the real-world telco benchmark for _decimal, replacing the
>> > single line
>> >
>> >     outfil.write("%s\n" % t)
>> >
>> > with
>> >
>> >     outfil.write("{}\n".format(t))
>> >
>> > adds 23% to the runtime. I think %-style formatting should not
>> > be deprecated at all.
>>    
>> When it becomes necessary, it's possible to optimize it by
>> hoisting out the name lookups.
>>    ...
>>    outfil_write = outfil.write
>>    append_newline = "{}\n".format
>>    ...
>>        outfil_write(append_newline(t))
>>        ...
>
> Did you profile this? I did, and it still adds 22% to the runtime.

No, I did not. And that's disappointing.

-- 
Neil Cerutti