Ezio Melotti <ezio.melo...@gmail.com> added the comment:
I did a few more tests and using a re.sub seems indeed slower (the
implementation is just 4 lines though, and it's more readable):
wolf@hp:~/dev/py/3.1$ ./python -m timeit -s 'import re,string; escape_pattern =
re.compile("([^\x00a-zA-Z0-9])")' 'escape_pattern.sub(r"\\\1",
string.printable).replace("\x00", "\\000")'
1000 loops, best of 3: 219 usec per loop
wolf@hp:~/dev/py/3.1$ ./python -m timeit -s 'import re,string'
're.escape(string.printable)'
10000 loops, best of 3: 59.3 usec per loop
wolf@hp:~/dev/py/3.1$ ./python -c 'import re,string; escape_pattern =
re.compile("([^\x00a-zA-Z0-9])"); print(escape_pattern.sub(r"\\\1",
string.printable).replace("\x00", "\\000") == re.escape(string.printable))'
True
wolf@hp:~/dev/py/3.1$ ./python -m timeit -s 'import re,string; escape_pattern =
re.compile(b"([^\x00a-zA-Z0-9])"); s = string.printable.encode("ascii")'
'escape_pattern.sub(br"\\\1", s).replace(b"\x00", b"\\000")'
1000 loops, best of 3: 231 usec per loop
wolf@hp:~/dev/py/3.1$ ./python -m timeit -s 'import re,string; s =
string.printable.encode("ascii")' 're.escape(s)'
10000 loops, best of 3: 73.2 usec per loop
wolf@hp:~/dev/py/3.1$ ./python -c 'import re,string; escape_pattern =
re.compile(b"([^\x00a-zA-Z0-9])"); s = string.printable.encode("ascii");
print(escape_pattern.sub(br"\\\1", s).replace(b"\x00", b"\\000") ==
re.escape(s))'
True
The .replace() doesn't seem to affect the affect the speed in any significant
way.
I also did a few more tests:
1) using enumerate();
2) like 1) but also moving \x00 in the set of alnum chars, removing the "if c
== '\000'" from the loop and using .replace("\x00", "\\000") on the joined
string;
3) like 2) but also moving the loop in a genexp inside the join();
1) is the fastest (10-15% faster than the original), 2) is pretty much the same
speed of 1), and 3) is slower, so I just changed re.escape to use enumerate()
and refactored its tests in 2.7/3.1/3.2/3.3.
----------
_______________________________________
Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue2650>
_______________________________________
_______________________________________________
Python-bugs-list mailing list
Unsubscribe:
http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
