Re: python vs. grep
2008/5/6, Anton Slesarev <[EMAIL PROTECTED]>: > But I have some problem with writing performance grep analog. [...] > Python code 3-4 times slower on windows. And as I remember on linux > the same situation... > > Buffering in open even increase time. > > Is it possible to increase file reading performance? The best advice would be not to try to beat grep, but if you really want to, this is the right place ;) Here is my code: $ cat grep.py import sys if len(sys.argv) != 3: print 'grep.py ' sys.exit(1) f = open(sys.argv[2],'r') print ''.join((line for line in f if sys.argv[1] in line)), $ ls -lh debug.0 -rw-r- 1 gminick root 4,1M 2008-05-07 00:49 debug.0 --- $ time grep nusia debug.0 |wc -l 26009 real0m0.042s user0m0.020s sys 0m0.004s --- --- $ time python grep.py nusia debug.0 |wc -l 26009 real0m0.077s user0m0.044s sys 0m0.016s --- --- $ time grep nusia debug.0 real0m3.163s user0m0.016s sys 0m0.064s --- --- $ time python grep.py nusia debug.0 [26009 lines here...] real0m2.628s user0m0.032s sys 0m0.064s --- So, printing the results take 2.6 secs for python and 3.1s for original grep. Suprised? The only reason for this is that we have reduced the number of write calls in the python example: $ strace -ooriggrep.log grep nusia debug.0 $ grep write origgrep.log |wc -l 26009 $ strace -opygrep.log python grep.py nusia debug.0 $ grep write pygrep.log |wc -l 12 Wish you luck saving your CPU cycles :) -- Regards, Wojtek Walczak http://www.stud.umk.pl/~wojtekwa/ -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
2008/5/6, Ben Finney <[EMAIL PROTECTED]>: > > > So why not put symlink to Python over there on all machines, if > > > we can put one (or env itself) there ? > > To avoid linking all the rest of interpreters like perl, ruby, lua > > and dozens of others. > The argument was being made from "thousands of scripts". Isn't "dozens > of symlinks" better? I think that depending on /usr/bin/env is more farsighted and saves some future headaches. Creating links in /usr/bin/ means, that you have to change them whenever you update your software (e.g. any of your many interpreters ;-)). Changing the "#!/usr/bin/python" into "#!/usr/bin/env python" means that you do your job once, and you can sleep well. It also is more portable. How was it in perl? perl -p -i -e 's/#\!\/usr\/bin\/python/#\!\/usr\/bin\/env python/' *.py Funny thing, I have just ls'ed /usr/bin/python on my system: $ ls -l /usr/bin/python lrwxrwxrwx 1 root root 24 2007-11-16 14:02 /usr/bin/python -> /usr/local/bin/python2.5 :-) -- Regards, Wojtek Walczak http://www.stud.umk.pl/~wojtekwa/ -- http://mail.python.org/mailman/listinfo/python-list
Re: #!/usr/bin/env python vs. #!/usr/bin/python
2008/5/6, Banibrata Dutta <[EMAIL PROTECTED]>: > > Use /usr/bin/env. If env is not in /usr/bin, put a link to it there. > > So why not put symlink to Python over there on all machines, if we can > put one (or env itself) there ? To avoid linking all the rest of interpreters like perl, ruby, lua and dozens of others. -- Regards, Wojtek Walczak http://www.stud.umk.pl/~wojtekwa/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Decimal vs Float comparasion
2008/5/6, Wojciech Walczak <[EMAIL PROTECTED]>:
> a > 9.0 returns True because NotImplemented > 9.0 returns True.
> a < 9.0 returns False because NotImplemented < 9.0 returns False.
Sorry, it should rather be:
Decimal('0.5') > 9.0 returns True because:
Decimal('0.5') > NotImplemented returns True
and:
Decimal('0.5') < 9.0 returns False because:
Decimal('0.5') < NotImplemented returns False
--
Regards,
Wojtek Walczak
http://www.stud.umk.pl/~wojtekwa/
--
http://mail.python.org/mailman/listinfo/python-list
Re: Decimal vs Float comparasion
2008/5/6, Yuan HOng <[EMAIL PROTECTED]>:
> It seems decimal object will always be larger than float in
> comparasion, which goes against common sense:
>
> >>> from decimal import Decimal
> >>> a = Decimal('0.5')
> >>> a > 9
> False
> >>> a > 9.0
> True
>
> It seems to me that rather than allowing this to happen, comparasion
> between the two should either be made correct (by convertion decimal
> to float e.g.) or forbidden, like arithmatic operations between the
> two types.
Looks like a nasty bug.
a > 9.0 returns True because NotImplemented > 9.0 returns True.
a < 9.0 returns False because NotImplemented < 9.0 returns False.
As you can see the real comparision has nothing to do with your Decimal number.
I think you can report it at bugs.python.org.
--
Regards,
Wojtek Walczak
http://www.stud.umk.pl/~wojtekwa/
--
http://mail.python.org/mailman/listinfo/python-list
Re: pygame music, cant read mp3?
2008/5/5, globalrev <[EMAIL PROTECTED]>:
> pygame.mixer.music.load('C:/Python25/myPrograms/pygameProgs/example1.mp3')
Are you sure that:
os.path.exists('C:/Python25/myPrograms/pygameProgs/example1.mp3') == True?
Check it with python.
--
Regards,
Wojtek Walczak
http://www.stud.umk.pl/~wojtekwa/
--
http://mail.python.org/mailman/listinfo/python-list
Re: confused about self, why not a reserved word?
2008/5/5, globalrev <[EMAIL PROTECTED]>: > class Foo(object): > def Hello(self): > print "hi" > > object is purple, ie some sort of reserved word. > > why is self in black(ie a normal word) when it has special powers. > replacing it with sel for example will cause an error when calling > Hello. Could you give an example of such an error? -- Regards, Wojtek Walczak http://www.stud.umk.pl/~wojtekwa/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Determine socket family at runtime
2008/5/4, Giampaolo Rodola' <[EMAIL PROTECTED]>: > For now I've been able to determine the family by using: > > # self.socket = a connected socket.socket instance > ip, port = self.socket.getsockname()[0:2] > af = socket.getaddrinfo(ip, port)[0][0] > > ...but I'd like to know if some other solution is preferable. Nope, there is none. Using getaddrinfo() to check address family is the de facto standard. -- Regards, Wojtek Walczak http://www.stud.umk.pl/~wojtekwa/ -- http://mail.python.org/mailman/listinfo/python-list
