🌐 Mailman 3 April 2003 - Python-list - python.org

Re: Is Python overhyped (just like Java)?
by David Abrahams April 1, 2003

April 1, 2003

"Delaney, Timothy C (Timothy)" <tdelaney(a)avaya.com> writes: >> From: David Abrahams [mailto:dave@boost-consulting.com] >> >> Also, it's only fair to point out that C++ doesn't have one library >> implementation -- each compiler comes with its own. Which >> implementation(s) were you testing? Oh, I see it was probably >> libstdc++ that comes with gcc 3.1. Well, IIRC GCC-3.1 was well >> known to optimize poorly (it took them some time to figure out how >> to integrate all the new optimizations that came in with GCC-3, and >> they actually made things slower for a while), and I wouldn't >> exactly say that libstdc++ is the fastest implementation. > > I think if you'll read the above, you will notice that Alex says > exactly the same thing "...with different implementations, you may see > different ratios." Quite right; I do see that. > Also, "read all the lines from a file" is not a primitive in Python - > it's a method call ... *and* it is written in C. That's what I mean by "a primitive". All of Python is written in C, so that's as primitive as things get. "Read all the lines from a file" can be specifically optimized for Python, whereas when you write the "obvious" code for it in C++, you're probably seeing overheads which reflect, e.g., buffering which makes sense for general-purpose I/O but which is a waste when reading all lines from a file. > Obviously there could be as good an implementation in C++ on the > same platform - whether there could be a *better* implementation is > another question. And another question is whether there could be a better implementation *for that particular job*. -- Dave Abrahams Boost Consulting www.boost-consulting.com

2 1

Locale and threads in python 2.1.3 and python 2.2.1
by jmv-lists＠linux-ink.ru April 1, 2003

April 1, 2003

Hello! Here's a simple example which works correctly when using 2.2.1 interpreter and fails under 2.1.3 (text.lower() result isn't in accordance with locale): ####################################### import time, locale from threading import Thread from thread import start_new_thread LOCALE='ru_RU.KOI8-R' TEXT='????? ? ????' class TestThread(Thread): def __init__(self): Thread.__init__(self) def run(self): print 'In thread: %s' % TEXT.lower() locale.setlocale(locale.LC_ALL, LOCALE) print 'After setlocale in thread: %s' % TEXT.lower() print 'Before setlocale: %s' % TEXT.lower() locale.setlocale(locale.LC_ALL, LOCALE) print 'After setlocale: %s' % TEXT.lower() t = TestThread() t.start() ####################################### I cannot switch to python 2.2 because 2.1 is still required by Zope. Does anyone know how to fix that without patching Zope to call setlocale in every thread? Eugene

1 0

Re: Is Python overhyped (just like Java)?
by Alex Martelli April 1, 2003

April 1, 2003

Steven Taschuk wrote: ... > What do templates have to do with interfaces? C++ templates, and "interfaces" (entirely abstract classes), are related by offering two separate approaches to obtaining polymorphism, with very different trade-offs. Python polymorphism is very close to the "generic programming" afforded by C++ templates, since both hinge on signature based polymorphism. However, Python's polymorphism is resolved at runtime, like that based on C++'s virtual-method calls, not at compile-time, like that afforded by C++'s templates, so the parallels are not exact. Alex

1 0

RE: Regular expression help
by Harvey Thomas April 1, 2003

April 1, 2003

Stephen Boulet wrote: > How do I use the sub function to replace my match with my match > prepended by a newline? > > Thanks. > > -- Stephen > Take advantage of the fact that the first argument of the sub method can be a function whose single argument is a match object: (Untested) def mysub(x): return '\n' + x.group(0) myregex.sub(mysub, mystring) or myregex.sub(lambda x: '\n' + x.group(0), mystring) For something as simple as this, I'd probably prefer the lambda form. Harvey _____________________________________________________________________ This message has been checked for all known viruses by the MessageLabs Virus Scanning Service.

1 0

changing icon to a Tkinter gui program
by Federico April 1, 2003

April 1, 2003

How can I change the icon of the windows of a Tkinter Gui program? Thanks

3 2

try:else: w/o except: - why not?
by manus＠python.net April 1, 2003

April 1, 2003

I know that if you want to use else: on a try: block, you need to specify one or more except: clauses. I guess my question is why this should need to be. Personally, I have cases where it would be nice to do this: try: # some code that may except else: # but if it didn't except, I want to do this Instead of writing the code that way, I need to write this: try: # some code that may except except: # and if it does, then, okay, just ignore it pass else: # but if it didn't except, I want to do this I know it's a core language decision and therefore up to Guido, but I am curious (Guido?) if there is something I am missing that would make a simple try:else: construction (without requiring any except: blocks) not make sense? Manus

8 8

GUI re builder
by Stephen Boulet April 1, 2003

April 1, 2003

Is there a GUI (tk) re builder that ships with python 2.2? I can't seem to find it. Thanks. Trying to build an re to match a date (of form 3/31/03 or 12/6/02, for example). Thanks. -- Stephen

3 3

using a private embedded python
by Bryan April 1, 2003

April 1, 2003

is there a common technique for embedding python with your application? i need to guarantee product stability and since python is completely open, anyone can build their own version or install multiple versions, or beta's, etc.. so, i'm forced to have our own verson of python installed in our own private location. if the end user wants to install python2.3a3 so be it, our product must run on 2.2.2 which our QA department as validated with our product. than means on windows, it'll probably end up being in program files/common files/<company>/python and moving the python22.dll from the windows directory there too. on unix maybe it's playing around with symlinks? my question is how can i guarantee that from PyInitialize() to PyFinalize() will use this private version? do i have to build a version of python22.dll that doesn't (on windows) look in the registry but is hard coded to another location? or should i modify sys.path to include only our python build area? can someone please point me in the right direction. thanks, bryan

4 7

Coordinating access to a non-thread-safe db
by VanL April 1, 2003

April 1, 2003

Hello, I am writing some code that needs to respond to two circumstances: 1. User input via an event-driven interface 2. The passing of a certain amount of time (a la cron) I am planning to use the sched and threading modules to do this. However, I need to access a database that is only threadsafe at level 1 (sqlite) and so I am unsure how to coordinate database access such that nothing gets corrupted. My initial thought was to implement a DBController thread, and defer all database access to that thread. However, I have not written very many multithreaded programs, and I am not sure that my intinct is correct. Does anyone have any experience or code that deals with this problem? Thanks, VanL

2 1

SimpleParse and LookAhead
by yvan_charpentier＠hotmail.com April 1, 2003

April 1, 2003

Hi, I must be missing something here. I was expecting the following script to get me: 'root', it outputs 'oot' Reading the docs, my understanding what that if '?' is a prefix, then the parser object returns to the previous location. Is that right? If not, how do i get that behaviour? declaration = r'''line := ?([a-z], root) root:= char ''' testdata = '''root - Dir ''' from simpleparse import generator from mx.TextTools import TextTools parser = generator.buildParser(declaration).parserbyname('line') taglist = TextTools.tag(testdata, parser) for tag, beg, end, parts in taglist[1]: print testdata[beg:end] Any help appreciated, -Yvan

2 1