Le jeudi 6 octobre 2011 02:06:30, Victor Stinner a écrit :
> The rfind case is really strange: the code between Python 3.2 and 3.3 is
> exactly the same. Even in Python 3.2: rfind looks twice faster than find:
>
> ("AB"*300+"C").find("BC") (*1000) : 1.21
> ("C"+"AB"*300).rfind("CA") (*1000) : 0.57
Le 06/10/2011 12:42, Victor Stinner a écrit :
"A".join(["Bob"]*100)): 0.92 => 2.11
I just optimized PyUnicode_Join() for such dummy benchmark. It's now
1.2x slower instead of 2.3x slower on this dummy benchmark.
With longer *ASCII* strings, Python 3.3 is now 2x (narrow 3.2) or 4x
(wide 3.2
Le 07/10/2011 03:19, Steven D'Aprano a écrit :
Given that strings are immutable, would it not be an obvious
optimization for replace to return the source string unchanged if the
old and new substrings are equal, and avoid making a potentially
expensive copy?
I just implemented this optimization
Steven D'Aprano wrote:
Given that strings are immutable, would it not be an obvious
optimization for replace to return the source string unchanged if the
old and new substrings are equal,
Only if this situation occurs frequently enough to outweigh
the overhead of comparing the target and repl
Victor Stinner wrote:
Hum, copy-paste failure, I wrote numbers in the wrong order, it's:
(test: Python 3.2 => Python 3.3)
"A".join(["Bob"]*100)): 0.92 => 2.11
("C"+"AB"*300).rfind("CA"): 0.57 => 1.03
("A" + ("Z"*128*1024)).replace("A", "BB", 1): 0.25 => 0.50
I improved str.replace(): it's now 5
Hum, copy-paste failure, I wrote numbers in the wrong order, it's:
(test: Python 3.2 => Python 3.3)
"A".join(["Bob"]*100)): 0.92 => 2.11
("C"+"AB"*300).rfind("CA"): 0.57 => 1.03
("A" + ("Z"*128*1024)).replace("A", "BB", 1): 0.25 => 0.50
I improved str.replace(): it's now 5 times faster instead of
Hi,
I optimized unicodeobject.c a little bit more where I saw major performance
regressions from Python 3.2 to 3.3 using stringbench. Here are new results:
see attachments. Example of tests where Python 3.3 is much slower:
"A".join(["Bob"]*100)): 2.11 => 0.92
("C"+"AB"*300).rfind("CA"): 0.57 =>
