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To: python-list@python.org
From: Terry Reedy <tjreedy@udel.edu>
Subject: Re: How do I display unicode value stored in a string variable using ord()
Date: Sun, 19 Aug 2012 17:03:46 -0400
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On 8/19/2012 1:03 PM, Blind Anagram wrote:

> Running Python from a Windows command prompt,  I got the following on
> Python 3.2.3 and 3.3 beta 2:
>
> python33\python" -m timeit "('abc' * 1000).replace('c', 'de')"
> 10000 loops, best of 3: 39.3 usec per loop
> python33\python" -m timeit "('ab=E2=80=A6' * 1000).replace('=E2=80=A6',=
 '=E2=80=A6=E2=80=A6')"
> 10000 loops, best of 3: 51.8 usec per loop
> python33\python" -m timeit "('ab=E2=80=A6' * 1000).replace('=E2=80=A6',=
 'x=E2=80=A6')"
> 10000 loops, best of 3: 52 usec per loop
> python33\python" -m timeit "('ab=E2=80=A6' * 1000).replace('=E2=80=A6',=
 '=C5=93=E2=80=A6')"
> 10000 loops, best of 3: 50.3 usec per loop
> python33\python" -m timeit "('ab=E2=80=A6' * 1000).replace('=E2=80=A6',=
 '=E2=82=AC=E2=80=A6')"
> 10000 loops, best of 3: 51.6 usec per loop
> python33\python" -m timeit "('XYZ' * 1000).replace('X', '=C3=A9=C3=A7')=
"
> 10000 loops, best of 3: 38.3 usec per loop
> python33\python" -m timeit "('XYZ' * 1000).replace('Y', 'p?')"
> 10000 loops, best of 3: 50.3 usec per loop
>
> python32\python" -m timeit "('abc' * 1000).replace('c', 'de')"
> 10000 loops, best of 3: 24.5 usec per loop
> python32\python" -m timeit "('ab=E2=80=A6' * 1000).replace('=E2=80=A6',=
 '=E2=80=A6=E2=80=A6')"
> 10000 loops, best of 3: 24.7 usec per loop
> python32\python" -m timeit "('ab=E2=80=A6' * 1000).replace('=E2=80=A6',=
 'x=E2=80=A6')"
> 10000 loops, best of 3: 24.8 usec per loop
> python32\python" -m timeit "('ab=E2=80=A6' * 1000).replace('=E2=80=A6',=
 '=C5=93=E2=80=A6')"
> 10000 loops, best of 3: 24 usec per loop
> python32\python" -m timeit "('ab=E2=80=A6' * 1000).replace('=E2=80=A6',=
 '=E2=82=AC=E2=80=A6')"
> 10000 loops, best of 3: 24.1 usec per loop
> python32\python" -m timeit "('XYZ' * 1000).replace('X', '=C3=A9=C3=A7')=
"
> 10000 loops, best of 3: 24.4 usec per loop
> python32\python" -m timeit "('XYZ' * 1000).replace('Y', 'p?')"
> 10000 loops, best of 3: 24.3 usec per loop

This is one test repeated 7 times with essentially irrelevant=20
variations. The difference is less on my system (50%). Others report=20
seeing 3.3 as faster. When I asked on pydev, the answer was don't bother =

making a tracker issue unless I was personally interested in=20
investigating why search is relatively slow in 3.3 on Windows. Any=20
change would have to not slow other operations or severely impact search =

on other systems. I suggest the same answer to you.

If you seriously want to compare old and new unicode, go to
http://hg.python.org/cpython/file/tip/Tools/stringbench/stringbench.py
and click raw to download. Run on 3.2 and 3.3, ignoring the bytes times.

Here is a version of the first comparison from stringbench:
print(timeit('''('NOW IS THE TIME FOR ALL GOOD PEOPLE TO COME TO THE AID =

OF PYTHON'* 10).lower()'''))
Results are 5.6 for 3.2 and .8 for 3.3. WOW! 3.3 is 7 times faster!

OK, not fair. I cherry picked. The 7 times speedup in 3.3 likely is at=20
least partly independent of the 393 unicode change. The same test in=20
stringbench for bytes is twice as fast in 3.3 as 3.2, but only 2x, not=20
7x. In fact, it may have been the bytes/unicode comparison in 3.2 that=20
suggested that unicode case conversion of ascii chrs might be made faster=
=2E

The sum of the 3.3 unicode times is 109 versus 110 for 3.3 bytes and 125 =

for 3.2 unicode. This unweighted sum is not really fair since the raw=20
times vary by a factor of at least 100. But is does suggest that anyone=20
claiming that 3.3 unicode is overall 'slower' than 3.2 unicode has some=20
work to do.

There is also this. On my machine, the lowest bytes-time/unicode-time=20
for 3.3 is .71. This suggests that there is not a lot of fluff left in=20
the unicode code, and that not much is lost by the bytes to unicode=20
switch for strings.

--=20
Terry Jan Reedy