Re: Cross platform Python app deployment
Hi, Will McGugan wrote: Is there some reference regarding how to package a Python application for the various platforms? I'm familiar with Windows deployment - I use Py2Exe InnoSetup - but I would like more information on deploying on Mac and Linux. The standard way to package portable Python apps is a tarball with a setup.py script. That should work on all systems where Python is already installed, including Windows. Read http://docs.python.org/dist/dist.html, if you have not already done so. If you want more 'native' packages (as you already have for Windows, where users are used to have a graphical installer), you'll have to create .deb, .rpm, .whatever packages. You usually won't have to bother about the Python interpreter, because it is either already present (it's a standard package on most systems) or it will be pulled in via a package dependency. distutils already allows you to create rpm packages. HTH -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Creating a daemon process in Python
Hello, Sakagami Hiroki wrote: What is the easiest way to create a daemon process in Python? Google says I should call fork() and other system calls manually, but is there no os.daemon() and the like? You could try http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/278731 HTH -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Creating a daemon process in Python
[EMAIL PROTECTED] wrote: On Feb 21, 9:33 am, Eirikur Hallgrimsson [EMAIL PROTECTED] wrote: Sakagami Hiroki wrote: What is the easiest way to create a daemon process in Python? I've found it even easier to use the built in threading modules: import time t1 = time.time() print t_poc.py called at, t1 import threading def im_a_thread(): time.sleep(10) print This is your thread speaking at, time.time() thread = threading.Thread(target=im_a_thread) thread.setDaemon(True) thread.start() t2 = time.time() print Time elapsed in main thread:, t2 - t1 Of course, your mileage may vary. That's not a daemon process (which are used to execute 'background services' in UNIX environments). -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: calling php function from python
Rob Wolfe wrote:
mark wrote:
is it possible to call a php function from python and use a class from
php in python? i want to use mmslib which creates mms messages and the
only implementation is a php mmslib implementation.
You can consider to use some kind of RPC (remote procedure call)
for example XML-RPC. This is a platform and language independent
solution.
Here you have some information:
http://www.faqs.org/docs/Linux-HOWTO/XML-RPC-HOWTO.html
http://groups.google.pl/group/comp.lang.python/msg/5a6ae6290593fc97
For a quickstart it's probably easier to run the PHP code using the CGI
version of the PHP interpreter. E.g.
os.system('/usr/bin/php mms.php')
or using the subprocess module, if you want to pass some data to the script
(using stdin/out).
As long as no remote PHP server is involved this is easier and perhaps even
faster than the RPC approach...
--
Benjamin Niemann
Email: pink at odahoda dot de
WWW: http://pink.odahoda.de/
--
http://mail.python.org/mailman/listinfo/python-list
Re: distutils: renaming setup.py ok?
Hello, Anastasios Hatzis wrote: I want to distribute Python site-packages. Is it okay to use other setup file names than setup.py, which is mentioned in any place I read in the doc? E.g., setupMySDK.py, setupMyLib.py It seems that it works with distutils at least - but probably doing so has side-effects with other tools which may expect exactly setup.py as file name. I'd say, it's mostly the user who is expecting setup.py as the filename. Perhaps 'setup.py --install-sdk' and 'setup.py --install-lib' would be more approriate (which can be done with distutils). HTH -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Inheriting str object
Marc 'BlackJack' Rintsch wrote:
In [EMAIL PROTECTED],
[EMAIL PROTECTED] wrote:
I want to have a str with custom methods, but I have this problem:
class myStr(str):
def hello(self):
return 'hello '+self
s=myStr('world')
print s.hello() # prints 'hello world'
s=s.upper()
print s.hello() # expected to print 'hello WORLD', but s is no longer
myStr, it's a regular str!
What can I do?
Return a `myStr` instance instead of a regular `str`:
def hello(self):
return myStr('hello ' + self)
yes, but the 'upper' method is the problem here.
So you'd have to override all string methods, like
class myStr(str):
...
def upper(self):
return myStr(str.upper(self))
And I'm not sure, if it then works in the intended way...
What you are probably looking for, is to extend the 'str' class itself, so
every str instance has your added functionality.
Don't know, if this is possible at all, but usually it's not a good idea to
mess with the bowels of Python unless you have some greater surgical
skills.
HTH
--
Benjamin Niemann
Email: pink at odahoda dot de
WWW: http://pink.odahoda.de/
--
http://mail.python.org/mailman/listinfo/python-list
Re: marshal.loads ValueError
Hello, abcd wrote: I have the following code which is sent over the wire as a string... from time import time class Foo: def go(self): print Time:, time() I get this code and store it as, data data = receivePythonSource() Then I try... exec marshal.loads(data) in my_module.__dict__ However I get an error saying: ValueError: invalid literal for __float__: om time import time class Foo: def go(self): almost like when I try to marshal and exec it misses the first two characters, fr ...any ideas? marshal is used to (de)serialize python objects from/to strings. marshal.loads() tries to deserialize an encoded string back into a python object - which does not make sense here. What you probably want is: exec data in my_module.__dict__ HTH -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Is there a better way to implement this:
Michael Yanowitz wrote: Hello: I wrote the code below (much irrelevant code removed). This doesn't quite work. What I wanted it to do was a) Execute function ftimed, which takes a function and a timeout in seconds. b) This will also execute function abort() as a thread. This function just runs for the specified number of seconds and returns. However, before it returns, throws an exception. c) If test() is still running when abort() is finished, ftimed() should catch the exception and return. It is catching the exception, however it continues running the function. Why does it continue and not return? The exception is raised in the thread that executes the abort() function. The exception does not get caught and terminates this thread. The other (main) thread is unaffected - exceptions are local to a thread and there is currently no (portable) way to raise an exception in another thread. What am I missing, or is there a better way to implement this (having ftimed() return when the abort-timer time is exceeded? You may use the signal.alarm() function, if you are on a UNIXoid system and you have only a signle time-out at a time (e.g. not nested). import time, thread, sys thread_finished = MAX RUN TIME EXCEEDED! def abort (seconds): start_time = time.time() while ((time.time() - start_time) seconds): time.sleep(0.01) any reason for not using time.sleep(seconds) here? print script run time exceeded max_run_time of, seconds, seconds. raise thread_finished return def test(): i = 0 while (True): time.sleep(1) print HELLO, i i+=1 def ftimed (func, seconds): thread.start_new_thread (abort, (seconds,)) try: func() except thread_finished: print Timeout return ftimed (test, 30) print Script finished -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: html + javascript automations = [mechanize + ?? ] or something else?
Hello, John wrote: John wrote: I have to write a spyder for a webpage that uses html + javascript. I had it written using mechanize but the authors of the webpage now use a lot of javascript. Mechanize can no longer do the job. Does anyone know how I could automate my spyder to understand javascript? Is there a way to control a browser like firefox from python itself? How about IE? That way, we do not have to go thru something like mechanize? I am curious about the webbrowser module. I can open up firefox using webbrowser.open(), but can one control it? Say enter a login / passwd on a webpage? Send keystrokes to firefox? mouse clicks? Not with the webbrowser module - it can only launch a browser. On the website of mechanize you will also find DOMForm http://wwwsearch.sourceforge.net/DOMForm/, which is a webscraper with basic JS support (using the SpiderMonkey engine from the Mozilla project). But note that DOMForm is in a early state and not developed anymore (according to the site, never used it myself). You could try to script IE (perhaps also FF, dunno..) using COM. This can be done using the pywin32 module https://sourceforge.net/projects/pywin32/. How this is done in detail is a windows issue. You may find help and documentation in win specific group/mailing list, msdn, ... You can usually translate the COM calls from VB, C#, ... quite directly to Python. HTH -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: UnboundLocalError
Hello,
Camellia wrote:
why it generates an UnboundLocalError when I do the following:
code
...
def main():
number = number()
number_user = user_guess()
while number_user != number:
check_number(number = number, number_user = number_user)
number_user = user_guess()
UnboundLocalError: local variable 'number' referenced before assignment
/code
I found when I changed the number() to num() or whatever the issue
solved
but doesn't every function has its own namespace?
Can anyone please explain it to me?
When Python compiles your code, it sees that you are using a local
variable 'number' in this function ('number = ...') and probably allocates
some memory for it or whatever - ask the core Python hackers for details.
When this statement is executed, the right hand side is evaluated first and
Python finds a reference to 'number'. It knows that number is a local
variable in main(), but has not been assigned yet (which would happend
after the right hand side is evaluated) - thus the error.
Even if you could get this to work, you have two 'number's in the function
with different meaning, which just makes understanding the code too
difficult.
Is number() (the global one) a function or class. I guess it's a function,
so I would suggest to name it 'get_number' (and same
for 'get_user_guess') - this makes the code more descriptive. Should it
really be a class, a common convention is to capitalize it 'Number()'.
HTH
--
Benjamin Niemann
Email: pink at odahoda dot de
WWW: http://pink.odahoda.de/
--
http://mail.python.org/mailman/listinfo/python-list
Re: Deprecation in String.joinfields()
Hello, Anoop wrote: I am getting the following error while trying to use deprecation Please help li = [a, b, mpilgrim, z, example] newname = string.joinfields (li[:-1], .) newname 'a.b.mpilgrim.z' newname = li[:-1].joinfields(.) Traceback (most recent call last): File interactive input, line 1, in ? AttributeError: 'list' object has no attribute 'joinfields' newname1 = string.join (li[:-1], .) newname1 'a.b.mpilgrim.z' newname = li[:-1].joinfields(.) Traceback (most recent call last): File interactive input, line 1, in ? AttributeError: 'list' object has no attribute 'join' Thank you for your help joinfields is just an alias for join and only the latter is a method of the string class (which should be used instead of the deprecated string.join function), which means that the string . has a method join which takes the list as an argument. So what you want should be written as: newname = ..join(li[:-1]) HTH -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Can I inherit member variables?
Hello, [EMAIL PROTECTED] wrote: I'm trying to work with the following idea: class animal: def __init__(self, weight, colour): self.weight = weight self.colour = colour class bird(animal): def __init__(self, wingspan): self.wingspan = wingspan print self.weight, self.colour, self.wingspan class fish(animal): def __init__(self, length): self.length = length print self.weight, self.colour, self.length So basically I have a base class (animal) that has certain attributes. When animal is inherited by a specific instance, further attributes are added, but I need to have access to the original attributes (weight, colour). When I run my code from within the derived class, self.weight and self.colour are not inherited (although methods are inherited as I would have expected). You'll have to invoke the __init__ method of the superclass, this is not done implicitly. And you probably want to add the weight and colour attributes to your subclass in order to pass these to the animal constructor. class fish(animal): def __init__(self, length, weight, colour): animal.__init__(self, weight, colour) self.length = length print self.weight, self.colour, self.length HTH -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Can I inherit member variables?
LorcanM wrote: Benjamin Niemann wrote: You'll have to invoke the __init__ method of the superclass, this is not done implicitly. And you probably want to add the weight and colour attributes to your subclass in order to pass these to the animal constructor. class fish(animal): def __init__(self, length, weight, colour): animal.__init__(self, weight, colour) self.length = length print self.weight, self.colour, self.length Thanks for the reply. I think there's a basic misunderstanding about the nature of inheritance on my side. What I want to do is instantiate the sub class (derived class) from within the animal class. I then expect the sub class to have inherited some basic properties that it knows it has (weight, colour). If I can expand the example I gave previously to try to make this a little clearer: class animal: def __init__(self, weight, colour): self.weight = weight self.colour = colour def describeMyself(self, type, measurement): if type == 'bird': myanimal = bird(measurement) elif type == 'fish': myanimal = fish(measurement) class bird(animal): def __init__(self, wingspan): self.wingspan = wingspan print I'm a bird, weight %s, colour %s, wingspan %s % (self.weight, self.colour, self.wingspan) class fish(animal): def __init__(self, length): self.length = length print I'm a fish, weight %s, colour %s, length %s % (self.weight, self.colour, self.length) Do you really want one animal instance to act both as bird and fish? Wouldn't it be more sensible to instanciate either bird or fish (animal being what is called an abstract class in other OOP languages)? bird and fish would then have their own implementation of describeMyself() with the 'print I'm a...' statement. I must admit that I don't really understand what you are trying to achieve... -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: why a main() function?
[EMAIL PROTECTED] wrote: I think I read a suggestion somewhere to wrap the code where a Python script starts in a main() function, so one has def main(): print hi main() instead of print hi What are the advantages of doing this? Refine this to: def main(): print hi if __name__ == __main__: main() The advantage of the 'if __name__ ..' statement is that you can import the script without running the 'main' code, e.g. from your unittest module. Wrapping the main code in a function allows you to call this function from your unittests and test it like any other function. Additionally I do usually add an 'argv' argument to main() which I use instead of sys.argv, so I can easily test it with different arguments. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: time.clock()
Tobiah wrote: The manual says: On Unix, return the current processor time as a floating point number expressed in seconds. So I ran this program: #!/usr/bin/python import time while 1: print time.clock() This gave me a stream of floats, the integer part of which only updated about every three seconds. Now, the manual also states: The precision, and in fact the very definition of the meaning of ``processor time'', depends on that of the C function of the same name So I man 3 clock and notice: The value returned is the CPU time used so far as a clock_t; to get the number of seconds used, divide by CLOCKS_PER_SEC. So, I'm wondering how to get that value from python. All I really want to do is know current time relative to a given point so that I can capture MIDI events, and store the time at which they arrive. Am I barking up the wrong tree? What you want sound like the 'wall clock' time. The CPU time is the time that the CPU spent on executing your process. And unless the process uses 100% of the CPU, CPU time will appear to be 'slower' than the wall clock. In your little program above the CPU spent about one third of the time on this process and the rest is used for other processes (e.g. updating the display). What you need is time.time(), if its precision is sufficient. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: MySQLdb not updating rows
Bowen wrote: import md5 import string import MySQLdb tc = raw_input(Teacher Code: ) p = raw_input(New Password: ) print tc hash = md5.new() hash.update(p) print p print hash.hexdigest() h = hash.hexdigest() boo = raw_input(Sure you want to update password with above details? Y or N: ) if boo == 'y': db = MySQLdb.connect(copweb2, **, **, ***) cursor = db.cursor() if cursor.execute(UPDATE teachers SET password = '%s' WHERE teacher_code = '%s' % (h, tc)): print Done else: print Error else: print cancelled cursor.close() db.close() This code doesn't seem to update my database, anyone any idea why? Is it me being stupid? It doesn't kick out an error at all. Another side note: don't build your queries using (dumb) string formatting, let the MySQLdb module do it for you. More specifically use: cursor.execute( UPDATE teachers SET password = %s WHERE teacher_code = %s, (h, tc) ) instead of cursor.execute( UPDATE teachers SET password = '%s' WHERE teacher_code = '%s' % (h, tc) ) The former form takes care of quoting and escaping, your version did not escape potentially harmful characters in tc, resulting in a possibly opened door for SQL injection attacks. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: urllib behaves strangely
Gabriel Zachmann wrote: Here is a very simple Python script utilizing urllib: import urllib url = http://commons.wikimedia.org/wiki/Commons:Featured_pictures/chronological; print url print file = urllib.urlopen( url ) mime = file.info() print mime print file.read() print file.geturl() However, when i ecexute it, i get an html error (access denied). On the one hand, the funny thing though is that i can view the page fine in my browser, and i can download it fine using curl. On the other hand, it must have something to do with the URL because urllib works fine with any other URL i have tried ... Any ideas? I would appreciate very much any hints or suggestions. The ':' in '..Commons:Feat..' is not a legal character in this part of the URI and has to be %-quoted as '%3a'. Try the URI 'http://commons.wikimedia.org/wiki/Commons%3aFeatured_pictures/chronological', perhaps urllib is stricter than your browsers (which are known to accept every b**t you feed into them, sometimes with very confusing results) and gets confused when it tries to parse the malformed URI. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: urllib behaves strangely
Benjamin Niemann wrote: Gabriel Zachmann wrote: Here is a very simple Python script utilizing urllib: import urllib url = http://commons.wikimedia.org/wiki/Commons:Featured_pictures/chronological; print url print file = urllib.urlopen( url ) mime = file.info() print mime print file.read() print file.geturl() However, when i ecexute it, i get an html error (access denied). On the one hand, the funny thing though is that i can view the page fine in my browser, and i can download it fine using curl. On the other hand, it must have something to do with the URL because urllib works fine with any other URL i have tried ... Any ideas? I would appreciate very much any hints or suggestions. The ':' in '..Commons:Feat..' is not a legal character in this part of the URI and has to be %-quoted as '%3a'. Oops, I was wrong... ':' *is* allowed in path segments. I should eat something, my vision starts to get blurry... Try the URI 'http://commons.wikimedia.org/wiki/Commons%3aFeatured_pictures/chronological', You may try this anyway... -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: GUI viewer for profiler output?
Kent Johnson wrote: Can anyone point me to a GUI program that allows viewing and browsing the output of the profiler? I know I have used one in the past but I can't seem to find it... If you use KDE, then you can convert the output of the hotshot profiler to into a format that KCachegrind can read (using a script called hotshot2calltree, which is part of KCachegrind). If anyone has a more direct solution, I'd be interested, too :) -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 3.0 or Python 3000?
Dennis Lee Bieber wrote: On Sun, 9 Apr 2006 22:15:15 -0400, Tim Peters [EMAIL PROTECTED] declaimed the following in comp.lang.python: [John Salerno] Is 'Python 3000' just a code name for version 3.0, or will it really be called that when it's released? The smart money is on changing the name to Ecstasy, to leverage marketing publicity from the hallucinogenic club drug of the same name. class will be renamed to rave, and the license will be changed to prohibit use by people with bipolar disorder. Either that, or the name will be Python 3.0. Or... just to save 3000 as a time way down the road... The next major version of Python will be: Python PI (and each build will add another digit... 3.1, 3.14, 3.141, ...) That's actually the versioning scheme of TeX, currently being at 3.141592 -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Why did someone write this?
Sandra-24 wrote: try: exc_type, exc_value, exc_traceback = sys.exc_info() # Do something finally: exc_traceback = None Why the try/finally with setting exc_traceback to None? The python docs didn't give me any clue, and I'm wondering what this person knows that I don't. You just have not found the right part of the doc: http://docs.python.org/lib/module-sys.html#l2h-337 -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: import random module
DataSmash wrote: Hi, When I import the random module at the python interpreter, it works fine: import random x = random.randint(1,55) print x 14 BUT, when I put the same code in a python script: * random.py: import random x = random.randint(1,55) print x and run it at the command line, I get: Traceback (most recent call last): File p:\temp\random.py, line 7, in ? import random File p:\temp\random.py, line 8, in ? x = random.randint(1,55) AttributeError: 'module object has no attribut 'randint' I run scripts at the command line everyday so there must be something specifically wrong with the random module, unless I'm totally missing something here. This is not specific to the random module, try: time.py: import time print time.time() Don't name your script 'random.py' (or any other name from the stdlib). 'import random' will import the script itself (not the random module from the stdlib), which is not what you want. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://pink.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Python version of XMLUnit?
Kent Johnson wrote: I have found XMLUnit to be very helpful for testing Java and Jython code that generates XML. At its heart XMLUnit is an XML-aware diff - it parses expected and actual XML and pinpoints any differences. It is smart enough to ignore things like attribute order, different quoting and escaping styles, and insignificant whitespace. Now I am working on a CPython project and have a similar need. Is there any comparable tool for Python? Basically I'm looking for a tool to compare XML and show diffs in an intelligible fashion that is usable from Python unit tests (using py.test, if it matters). http://www.logilab.org/projects/xmldiff You'd still have to integrate this into your test framework though... And I'll have a look at XMLUnit - seem's like something I could use for my current project ;) -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Another stupid newbie question
Byte wrote: How can I make the following code: from random import random def stuff(a, mx): x = 2 while x == 2: x = random() if x == mx: print x else: print 'No luck,', x x = 2 Stop when x == mx? What's the intention behind setting x = 2 at all? def stuff(a, mx): while True: x = random() if x == mx: print x else: print 'No luck,', x Should do the same as you're code above. If stuff will never be called with mx=None, I would suggest using def stuff(a, mx): x = None while x != mx: x = random() if x == mx: print x else: print 'No luck,', x Also note that random() returns a float and it is *very* unlikely that the condition x == mx will ever come true -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Apparent eval() leak for python 2.3.5
John Marshall wrote: Hi, I am reposting this message from python-dev. Could someone please test the code below to verify that there is indeed a problem with eval() under python 2.3.5. I have rebuilt python 2.3.5 under the latest debian and under RH 7.3 (in case the problem is in system libraries). The following code causes the virtual memory allocation to constantly increase until there is no more memory left (the VIRT column of the 'top' utility display). I have this leak, too in python2.3 under debian/sid: Python 2.3.5 (#2, Nov 20 2005, 16:40:39) [GCC 4.0.3 2005 (prerelease) (Debian 4.0.2-4)] on linux2 python2.4 seems to be unaffected. Python 2.4.2 (#2, Nov 20 2005, 17:04:48) [GCC 4.0.3 2005 (prerelease) (Debian 4.0.2-4)] on linux2 -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: python encoding bug?
[EMAIL PROTECTED] wrote:
I was playing with python encodings and noticed this:
[EMAIL PROTECTED]:~$ python2.4
Python 2.4 (#2, Dec 3 2004, 17:59:05)
[GCC 3.3.5 (Debian 1:3.3.5-2)] on linux2
Type help, copyright, credits or license for more information.
unicode('\x9d', 'iso8859_1')
u'\x9d'
U+009D is NOT a valid unicode character (it is not even a iso8859_1
valid character)
It *IS* a valid unicode and iso8859-1 character, so the behaviour of the
python decoder is correct. The range U+0080 - U+009F is used for various
control characters. There's rarely a valid use for these characters in
documents, so you can be pretty sure that a document using these characters
is windows-1252 - it is valid iso-8859-1, but for a heuristic guess it's
probably saver to assume windows-1252.
If you want an exception to be thrown, you'll need to implement your own
codec, something like 'iso8859_1_nocc' - mmm.. I could try this myself,
because I do such a test in one of my projects, too ;)
The same happens if I use 'latin-1' instead of 'iso8859_1'.
This caught me by surprise, since I was doing some heuristics guessing
string encodings, and 'iso8859_1' gave no errors even if the input
encoding was different.
Is this a known behaviour, or I discovered a terrible unknown bug in
python encoding implementation that should be immediately reported and
fixed? :-)
happy new year,
--
Benjamin Niemann
Email: pink at odahoda dot de
WWW: http://www.odahoda.de/
--
http://mail.python.org/mailman/listinfo/python-list
Re: can modules be dynamically reloaded
Steve wrote: Can python modules be reloaded. Yes: import mymod ... reload(mymod) But this will not always work as expected (what someone would expect who does not really understand how it works...). Read the documentation on http://docs.python.org/lib/built-in-funcs.html#l2h-59 For example you import a module, programatically edit it, then have the file reload the module? Does anyone have any ideas about this? Steve -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Making a persistent HTTP connection
Diez B. Roggisch wrote: David Rasmussen wrote: I use urllib2 to do some simple HTTP communication with a web server. In one session, I do maybe 10-15 requests. It seems that urllib2 opens op a connection every time I do a request. Can I somehow make it use _one_ persistent connection where I can do multiple GET-receive data passes before the connection is closed? Are you sure HTTP supports that? This would be news to me - which doesn't mean much :) It does (HTTP/1.1 at least) and it's called 'keep-alive'. And even if it works - what is the problem with connections being created? Performance, network load... -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Python's website does a great disservice to the language
Steven D'Aprano wrote: http://www.python.com/ perhaps? Yep, let's make this the new official python site ;) -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: How to translate python into C
Johnny Lee wrote: Hi, First, I want to know whether the python interpreter translate the code directly into machine code, or translate it into C then into machine code? Neither this nor that. The interpreter first compiles the code into python 'byte code' - something similar to machine code, but not it is not targeted at the CPU of your system, but for a portable virtual machine. This virtual machine will then execute the byte code, just like a CPU would execute machine code. Second, if the codes are translated directly into machine codes, how can I translate the codes into C COMPLETELY the same? if the codes are translated first into C, where can I get the C source? You may have a look at PyPy. I do not know what it exactly can do, but this might be interesting for you: http://codespeak.net/pypy/dist/pypy/doc/faq.html#how-do-i-compile-my-own-programs -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Pickle to source code
Gabriel Genellina wrote: I want to convert from pickle format to python source code. That is, given an existing pickle, I want to produce a textual representation which, when evaluated, yields the original object (as if I had unpickled the pickle). I know of some transformations pickle/xml (Zope comes with one such tool, gnosis xml is another) so I believe I could build something based on them. But I dont want to reinvent the wheel, I wonder if anyone knows of a library which could do what I want? If all objects correctly implement the __repr__ method (true for built-in stuff like list, dict, set...): Just unpickle it and call repr() on the resulting object. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Question about StringIO
Frank Millman wrote: I will try to explain my experience with popen() briefly. I have some sql scripts to create tables, indexes, procedures, etc. At present there are about 50 scripts, but this number will grow. I have been running them manually so far. Now I want to automate the process. I am supporting PostgreSQL and MS SQL Server, and the syntax is slightly different in some cases. Rather than maintain two sets of scripts, I prefix some lines with -pg- or -ms- to indicate the platform, and then use Python to parse the scripts and generate a correct output for each platform, passing it to 'psql' and 'osql' respectively, using popen(). I have had a few problems, but it would take too long to describe them all, and I just want a working solution, so I will focus on my latest attempt. I run through all the scripts and create a StringIO object with the string I want to pass. It is about 250 000 bytes long. If I run psql using popen(), and pass it the string via stdin, it works fine, but I get all the messages on the screen. If I do the same, but end the command with ' fjm 21' it works correctly and the messages end up in the file fjm, which is about 40 000 bytes long. If I run it with popen4(), it starts ok, but then hangs about 1/4 of the way through. Exactly the same happens on MSW. It seems to be hitting a limit on the size of the stdout file - is that possible? For my purposes, I will be happy to use popen() and a choice of no redirection, redirect to a file, or redirect to /dev/null. The question about popen4() is therefore academic, though I would be interested to know the answer. That's probably a deadlock as described in http://docs.python.org/lib/popen2-flow-control.html BTW, is there an equivalent of /dev/null on MSW? Dunno - but as a last resort, you could create a tempfile with a unique name (to be sure, not to override any existing data), dump your output there and later os.unlink() it... -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: how to get the return value of a thread?
Leo Jay wrote: Dear all, i would like to get the return value of all threads e.g. def foo(num): if num10: return 1 elif num50: return 2 else return 0 after i invoked t = thread.start_new_thread(foo,(12,)) how to get the return value of `foo'? Take a look at the Queue module. Create a queue instance at let the 'foo thread' put() its result into it: fooResult = Queue.Queue() def foo(num): result = 0 if num10: result = 1 elif num50: result = 2 fooResult.put(result) t = thread.start_new_thread(foo,(12,)) # do other stuff, foo is running in background r = fooResult.get() # guaranteed to block until result is available print r -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: ~ after script filename?
presentt wrote: Hello all, I just wrote a really simple script and named it helloworld.py. Inside was only: #!/usr/bin/env print Hello, world I used chmod to set the permissions, and ran it to see what happened (I just started learning Python, if you couldn't guess) Then, I typed ls in the directory to see what was there, and I noticed a new file, namely helloworld.py~ . What is that file (its contents are identicle to helloworld.py)? Why the ~? Thanks a lot. I'm using Ubuntu Linux 5.04 (Hoary), and wrote the script with gedit. ~~Ted Present As others have already said: this is not a python issue. A ~ suffix is commonly used by editors for backup file. If you save a file from the editor, and the file already exists (so it doesn't happen the first time you save a new file), the existing version is renamed with the ~ suffix. After some time, you will learn to simply ignore these files ;) Many file managers have already learnt this lesson and have options to hide such backup files. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Is my thread safe from premature garbage collection?
[EMAIL PROTECTED] wrote: Hello all, I'm aware that in Python an object is cleared for garbage collection as soon as the last reference to it disappears. Normally this is fine. However, in my current project I'm creating a bunch of threads which are supposed to run until they've completed their run() method, and I'm worried that if I do not keep references to these thread objects around, the GC might happily delete them (and thereby kill my thread routines maybe?) while they're not done yet. Is this fear justified? Or is the Python GC smart enough to leave thread objects alone until their run() methods have finished? If not, I do have a workaround, but it is a bit clumsy IMO. Basically I would just keep a list into which each thread object enters a reference to itself on creation. This way I'd ensure that I have a reference to the thread to prevent the GC from killing it. Then, when a thread is about to finish its run() method, the thread finds and removes that reference to itself from my list of thread references. Anyway, if anyone could make a definite statement on whether threads are safe from unwanted garbage collection, that'd be really great. Thanks in advance for any helpful replies! The threading module does already take care of keeping references to all running threads, so there's no need to do it yourself and your threads are safe from being garbage collected. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Decrypting GPG/PGP email messages
posted mailed Alessandro Bottoni wrote: I know you will shake you head sadly but... I really have to perform such a suicidal task (even if for a short time and just for internal use). I have to send by email (over the open internet) a XML file containing _system commands_ (yes: the kind of stuff like rm -dfr /) to a server and have a Python program sitting on this server, fetching and parsing the e-mail message and executing the commands (maybe with _root privileges_). Of course, I want to be sure that only the allowed people is able to send such dangerous messages to my server so I will ask my users to encrypt and digitally sign their messages using Thunderbird, Enigmail and GPG as described in this very fine tutorial: http://goldenspud.com/webrog/archives/2005/03/10/encrypt-encrypt/ So far, so good, but I still have a couple of doubts about the server side: 1) What would you use to decrypt the messages? The GPG module created by Andrew Kuchling is declared incomplete and no more maintained on his web pages (http://www.amk.ca/python/code/gpg) so I think it is out of the game. Would you use OpenPGP (http://www.aonalu.net/openpgp/python)? Any other module? What about using the command line program via os.pipeX(gpg...)? I've done it this way when I needed to _create_ encrypted mail attachments using python (you'll need different gpg options for decrypting): pipe_in, pipe_out = os.popen2(/usr/bin/gpg -q -r KEYID -s --passphrase-fd 0 --batch --no-tty -a -o - -e '%s' % path_to_temporary_file) pipe_in.write(passphrase) pipe_in.close() # read encrypted file from pipe_out pipe_out.close() 2) I did not find any mention of _encrypted attachments_ on the Net. Does anybody know of a tutorial or a guide that explains how to encrypt (with Thunderbird/Enigmail) and decrypt (with Python) the (ANSI text) files attached to a email message? I can't help you with Thunderbird. In the worst case, you'll have to encrypt your command file manually and attach the encrypted version to your mail. KMail does have checkboxes for encrypt/sign every attachment separately... -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Is my thread safe from premature garbage collection?
Sion Arrowsmith wrote: In article [EMAIL PROTECTED], Benjamin Niemann [EMAIL PROTECTED] wrote: [EMAIL PROTECTED] wrote: However, in my current project I'm creating a bunch of threads which are supposed to run until they've completed their run() method, and I'm worried that if I do not keep references to these thread objects around, the GC might happily delete them (and thereby kill my thread routines maybe?) while they're not done yet. Is this fear justified? The threading module does already take care of keeping references to all running threads, The implementation of threading.enumerate() would be entertaining if it didn't. Quite apart from which, I presume the OP's run() method looks something like: class MyThread(threading.Thread): def run(self): ... So what is self if not a reference to the Thread object which is kept around until run() has completed? This was just too obvious;) Looking at the sourcecode of the threading module and discovering the 'limbo' dict, where every thread stores a reference to itself, was certainly more entertaining. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: is there a better way to check an array?
jdonnell wrote: I want to check if a value is in an array. I'm currently doing it as follows, but I just don't like this way of doing it. It seems unpythonic. fieldIsRequired = true try: notRequiredAry.index(k) fieldIsRequired = false except ValueError: pass # throw expception if field is required and is empty if(product[k] == '' and fieldIsRequired): raise GMError(k + ' is required') if product[k] == '' and k in fieldIsRequired: raise GMError(k + ' is required') -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: time.strptime() for different languages
Adam Monsen wrote: Anyone know of something that works like time.strptime(), but for other languages? Specifically, Dutch (ex: 31 augustus 2005, 17:26) and German? Thinking out loud... since 31 augustus 2005, 17:26 is only different by month name, I suppose I could just substitute the month name using a translation table for English to Dutch month names. Have you tested it with the proper locale setting and strptime(dateString, %c)? I have not ;) -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Dynamic image creation for the web...
Tompa wrote:
Hi,
I would like to create images on the fly as a response to an http request.
I can do this with PIL like this (file create_gif.py):
from PIL import Image, ImageDraw
print 'Status: 200 OK'
print 'Content-type: text/html'
print
print 'HTMLHEADTITLEPython Dynamic Image Creation
Test/TITLE/HEAD' print 'BODY'
im = Image.new(P, (600, 400))
draw = ImageDraw.Draw(im)
draw.rectangle((0, 0) + im.size, fill=blue)
im.save(images/tmp.gif);
print 'img src=/scripts/images/tmp.gif'
print '/BODY'
However, I would like to 1) avoid saving the image in a file on disk and
2) separate the HTLM code from the python image creation code.
Something like this is what I have in mind:
(file index.html):
html
headmeta HTTP-EQUIV=content-type CONTENT=text/html; charset=UTF-8
titlePython Dynamic Image Creation/title
/head
IMG SRC=/scripts/create_image.py ALT=Image created on the fly...
/html
and in file create_image.py:
from PIL import Image, ImageDraw, ImageFont
im = Image.new(P, (600, 400))
draw = ImageDraw.Draw(im)
draw.rectangle((0, 0) + im.size, fill=blue)
Unfortunately this does not work :-(
What is missing?
You are almost there. Your create_image.py does not return anything to the
browser yet.
First return proper HTTP headers, e.g.
sys.stdout.write('Status: 200 OK\r\n')
sys.stdout.write('Content-type: image/gif\r\n')
sys.stdout.write('\r\n')
(Your prints above are mostly equivalent, but do not output the correct \r\n
as line terminator - at least on UNIX style systems. Most webservers
tolarate this, if it's coming from a CGI - but doing it right and not
relying on a certain server behaviour is not bad anyway ;)
Then check the PIL docs to find out, how to output the image to sys.stdout
(instead of writing to a file).
--
Benjamin Niemann
Email: pink at odahoda dot de
WWW: http://www.odahoda.de/
--
http://mail.python.org/mailman/listinfo/python-list
Re: Dynamic image creation for the web...
Tompa wrote:
Benjamin Niemann pink at odahoda.de writes:
You are almost there.
I don't feel so...
Your create_image.py does not return anything to the
browser yet.
Yes, I am aware of that but I do not what to return.
First return proper HTTP headers, e.g.
sys.stdout.write('Status: 200 OK\r\n')
sys.stdout.write('Content-type: image/gif\r\n')
sys.stdout.write('\r\n')
Ok, but if possible I'd rather not return anything HTTP/HTML-related from
my create_image.py file.
When the browser fetches the images for displaying, it performs just another
HTTP request, and you must reply with a valid HTTP response. The
Content-type header is the absolute minimum that must always be returned.
(IIRC the 'Status' can be omitted, if it's 200).
Then check the PIL docs to find out, how to output the image to
sys.stdout (instead of writing to a file).
Ok, then I get this:
from PIL import Image, ImageDraw
import sys
im = Image.new(P, (600, 400))
draw = ImageDraw.Draw(im)
draw.rectangle((0, 0) + im.size, fill=blue)
sys.stdout.write('Status: 200 OK\r\n')
sys.stdout.write('Content-type: image/gif\r\n')
sys.stdout.write('\r\n')
im.save(sys.stdout, GIF)
But this does not work.
I also tested to skip the HTTP-header stuff and just write the gif to
sys.stdout, believing that that would work. But not so...
Works perfectly here...
What does the error.log of the webserver say?
Hmm, I'm a newbie to Python (as you already probably have noticed ;-) so I
don't know what else I should try. Any hints are welcome!
/Tompa
--
Benjamin Niemann
Email: pink at odahoda dot de
WWW: http://www.odahoda.de/
--
http://mail.python.org/mailman/listinfo/python-list
Re: Speed quirk: redundant line gives six-fold speedup
Raymond Hettinger wrote: Mark Dickinson wrote: I have a simple 192-line Python script that begins with the line: dummy0 = 47 The script runs in less than 2.5 seconds. The variable dummy0 is never referenced again, directly or indirectly, by the rest of the script. Here's the surprise: if I remove or comment out this first line, the script takes more than 15 seconds to run. So it appears that adding a redundant line produces a spectacular six-fold increase in speed! Thanks for your post. It is cute, brilliant, and interesting. I haven't had time to investigate but can point at the likely cause. All of the global names are stored in a single hash table. Search time is dictated by two factors, the sparseness of the hash table and the distribution of hash values. With respect to sparseness, whenever that table becomes 2/3 full, it grows by a factor of four and becomes only 1/6 full (leading to many fewer collisions). With respect to distribution, it should be noted that string hash values are decidely non-random and your variable names likely congested consecutive spaces in a nearly full table (resulting in seven times as many search probes to find a global value). When the extra value was added, it likely resized the table four-fold and redistributed the hash values into fewer consecutive positions. If that's the cause, then here's another reason to use long, descriptive names instead of C64-BASIC style a, b, c, i, j... - with long names the chances of hash collisions are pretty low. Or everyone will start optimizing their programs by using long, *random* names ;) -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Warning when doubly linked list is defined gloablly
chand wrote: Hi., In my api.py file 'g_opt_list' is defined globally g_opt_list =[[],[],[],[],[],[],[]] I am using this global list in the fucntion def function (): gloabl g_opt_list global? when I run the py file, I am getting the Following Error SyntaxWarning: name 'g_opt_list' is used prior to global declaration Please let me know how to remove this error This happens in cases like a = 1 def c(): ... a ... global a Does your source only consist of the three lines above? (These would trigger a SyntaxError because of the typo...) You should provide a more complete example, so we can tell you where the problem is. Try to build a minimal file that reproduces the problem. Often you will find the line causing the error yourself - and the fix might be obvious to you -, if your strip stuff away. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: DeprecationWarning: Non-ASCII character '\xf3'
jau wrote: Hi co-listers! I have been off Python for 2 years and now, that i'm used to Eclipse and Java, I decided to start a project with Python to refresh skills this time using Eclipse and TrueStudio. But now, two things can be occured since the last time i used it. the first one, something concerning to the encoding has changed and i haven't noticed it. the other one, when using Python from Eclipse i have to add any special config lines at the begining of my Python files. if i have this hello world python program (i have to call it by someway, hahaha) print hello world i get this output hello world sys:1: DeprecationWarning: Non-ASCII character '\xf3' in file C:\Workspace\JJ\src\es\jau\main.py on line 2, but no encoding declared; see http://www.python.org/peps/pep-0263.html for details the article mentioned above didn't explain so much for me. i doesn't look to be an error, but curiosity is bitting me... what's really happening here? Do I need to do any special thing to avoid this? The single print statement above should not trigger this warning. Are there any non-ASCII character in the file (perhaps comments?). If you use non-ASCII characters in python source files, you have to tell the interpreter which encoding you are using - otherwise funny things will happen. You have to find out which encoding Eclipse uses to save file (looks like iso-8859-1) and add the line # -*- coding: iso-8859-1 -*- at the top of the file. Python does not make any assumptions about the encoding beyond US-ASCII (perhaps it does, but it does not encourage taking advantage of this) - if you use anything else, then you'll have to declare it. This will be important, if you use unicode strings: ustränge characters Python must know the encoding of the file in order to decode the string literal into an unicode string. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: loop in python
km wrote: Hi all, thing. If *all* your loops are going to do is print stuff, then you're doing the right thing with the version that emits values. ya most of the loops print values. In that case, you are interested in IO performance. The time spent handling the loop is not significant compared to the time spent executing the 'print' statement - which is a very complex operation despite its simple usage. An implementation where a simple control flow structure has an measurable impact on the overall timing of an IO bound program would really suprising. Python suprises me often, but in different ways ;) Perhaps you could try to use sys.stdout.write() directly, avoiding the overhead of 'print'. Perhaps there are differences between the (default) output buffering settings of perl and python. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Adobe COM with Python
Andy W wrote: I'm wanting to automate Adove Acrobat Reader using Com thru Python and win32com, but i can't find any documentation for the Adobe stuff? Has anyone done anything with Acrobat COM ? I've searched Google groups and the web but am unable to find anything. I have not hacked Acrobat yet, but done a bit with InDesign - Adobe's documentation is less than perfect, but still pretty good. You might look at http://partners.adobe.com/public/developer/acrobat/sdk/index_doc.html#js - in InDesign I could easily map the methods and attributes from the JS documentation to COM calls (the JS members start with lowercase - e.g. 'properties' -, while COM need uppercase - 'Properties'). -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Save Binary data.
GMane Python wrote: Hello All. I have a program that downloads 'gigabytes' of Axis NetCam photos per day. Right now, I set up the process to put the images into a queue, and every 30 or so seconds, 'pop' them from the queue and save them to disc. I save them as individual files. I think that I'd like to modify it to save into one file 100-200 images, so that I don't have directories with 50,000-90,000 frames before handing that off to a DivX Encoder. I don't know if I need to use something like cPickle, or maybe just save them as a binary data file (which would be a temp file until later in the day when I open it to begin the encoding process.) Can someone please help me with some direction? You could use the tarfile module to create a single file holding a arbitrary number of files - including compression, if you want, but if your images are JPEGs then further compression is mostly a waste of CPU cycles. You can extract the images later on with either a python script and tarfile or using the standard commandline tool 'tar'. If the images are uncompressed anyway, you could have a look at the netpbm suite and its fileformat (which is pretty simple, but uncompressed and would bloat JPEGs to a multiple of the original filesize) which supports 'image sequences'. Perhaps a DivX encoder could even support this fileformat directly as input. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: stopping a python windows service
DK wrote: i was able to successfully create a windows service using py2exe. it polls a website periodically and logs it to a file. this is done using a function that does an infinite loop with periodic sleeps. my question is... what's the best way to stop this service gracefully? when try to stop it from the services applet from control panel, it takes forever and then gives me an error. currently, the only way i am able to stop it is using the task manager and killing the process. Windows services generally use two threads: one to do the work and one to listen for messages from the whatever-the-component-is-called-to-control-services. When the message thread received a 'stop' message, it should inform the worker thread to shut down, e.g. using threading.Event. So your worker should regularily check for the shutdown event, e.g.: while not shutdownEvent.isset(): pollWebsite() for i in xrange(1800): if shutdownEvent.isset(): break time.sleep(1) But if you get the 'stop' message while the worker thread is in pollWebsite() and the webserver is slw, you'll still have a significant delay... To avoid this, you would need a http client based on select() that allows you to check shutdownEvent.isset() at certain intervals - instead of urlopen which just blocks. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Compile time checking?
[EMAIL PROTECTED] wrote: On Fri, 12 Aug 2005 22:25:07 -0700 Steve Jorgensen wrote: Since Python does not use manifest typing, there's not much you can do about this, but typeless languages like this are great if you're using a process that finds the errors the compiler would otherwise find. I'm referring, of course, to Test Driven Development (TDD). If you do TDD, you won't miss compile-time checking much. In fact, the extra kruft that manifest typing requires is an annoying burden when doing TDD, so Python is a breath of fresh air in this regard. What test should one implement to catch that kind of errors like in OP example? A 'good' testsuite should run each line of the code at least once. There's more to do for a good code coverage, but that's the most basic requirement. So the faulty line will be executed by the testsuite and the runtime checking will raise an exception. Static typing is a very rudimentary type of code checking that is performed by the compiler with 100% code coverage. Such test won't tell you, if your code is actually doing what it is supposed to do (or anything sensible at all) and are mostly useless. If you think that code quality is important, you'll have to perform much more and more sophisticated tests. Such a testsuite is usually (I can't think of cases where it is not) a superset of static code checking - all type bugs are found be the testsuite even in the absence if static type checking. So you won't loose anything, if you drop static typing. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Help with Regular Expressions
Harlin Seritt wrote: Forgive another question here, but what is the 'r' for when used with expression: r'\w+...' ? r'..' or r.. are raw strings where backslashes do not introduce an escape sequence - so you don't have to write '\\', if you need a backslash in the string, e.g. r'\w+' == '\\w+'. Useful for regular expression (because the re module parses the '\X' sequences itself) or Windows pathes (e.g. r'C:\newfile.txt'). And you should append a '$' to the regular expression, because r[EMAIL PROTECTED] would match '[EMAIL PROTECTED]', too. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Compile time checking?
Qopit wrote: [snip] My questions are: - Am I missing something with my tester example? - Are there other code-checking options other than PyChecker? Try pylint -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: about coding
cantabile wrote: Hi, being a newbie in Python, I'm a bit lost with the '-*- coding : -*-' directive. I'm using an accented characters language. Some of them are correctly displayed while one doesn't. I've written : -*- coding: utf-8 -*- Is this wrong ? Where can I find a pratical explanation about these encodings ? The coding line tell the interpreter to assume that the file is encoded as utf-8. It's the job of the editor that you are using, to actually encode the file as utf-8. The coding directive uses a format that is automatically recognized by the emacs editor. If you are using another editor, you'll have to search its menus for the proper way to save files as utf-8. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Putting function references in a Queue
Richard Townsend wrote: I've been experimenting putting a reference to a function into a Queue object and was wondering what actually gets put in the Queue - is it the function's code object? No, it's justa referenceto the function object. If I read from the Queue in a different module, it appears that I don't need to import the module that defines the function - or any module that it uses - is this generally true, or are there some conditions to be aware of? There function reference is sufficient to call the function, there's not need to import the module containing the function. It has already been imported (otherwise the function wouldn't be there) and the function has a reference to this module in order to resolve its global (module-level) references. The scenario I'm working on has child threads doing some tasks and then sending back tuples (done, function, args, kwargs) via the Queue, to be called in the main thread. The Python code is ultimately embedded in a C/Motif app. As long as you take care of the usual threading issues (concurrent access to shared objects guarded by semaphores etc.), there should not be any greater problems. The function will be executed in the thread that is called it of course (and not in the thread that sent the reference to it). -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Py: a very dangerous language
Luis M. Gonzalez wrote: This is great! It's absolutely useless, like a real therapist, but it's free! Never heard of Eliza? Even Emacs has it built in (Menu Help - Emacs Psychiatrist). -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: minidom xml non ascii / unicode files
webdev wrote:
lo all,
some of the questions i'll ask below have most certainly been discussed
already, i just hope someone's kind enough to answer them again to help
me out..
so i started a python 2.3 script that grabs some web pages from the web,
regex parse the data and stores it localy to xml file for further use..
at first i had no problem using python minidom and everything concerning
my regex/xml processing works fine, until i tested my tool on some
french page with non ascii chars and my script started to throw errors
all over the place..
I've looked into the matter and discovered the unicode / string encoding
processes implied when dealing with non ascii texts and i must say i
almost lost my mind.. I'm loosing it actually..
The general idea is:
- convert everything that's coming in (from the net, database, files) into
unicode
- do all your processing with unicode strings
- encode the strings to your preferred/the required encoding when you write
it to the net/database/file
so here are the few questions i'd like to have answers for :
1. when fetching a web page from the net, how am i supposed to know how
it's encoded.. And can i decode it to unicode and encode it back to a
byte string so i can use it in my code, with the charsets i want, like
utf-8.. ?
First look at the HTTP 'Content-Type' header. If it has a parameter
'charset', that the encoding to use, e.g.
Content-Type: text/html; charset=iso-8859-1
If there's not encoding specified in the header, look at the ?xml .. ?
prolog, if you have a XHTML document at hand (and it's present). Look below
for the syntax.
The last fallback is the meta http-equiv=Content-Type content=... tag.
The content attribute has the same format as the HTTP header.
But you can still run into UnicodeDecodeErrors, because many website just
don't get their encoding issues right. Browser do some (more or less)
educated guesses and often manage to display the document as intended.
You should probably use htmlData.encode(encoding, ignore) or
htmlData.encode(encoding, replace) to work around these problems (but
loose some characters).
And, as said above: don't encode the unicode string into bytestrings and
process the bytestrings in your program - that's a bad idea. Defer the
encoding until you absolutely necessary (usually file.write()).
2. in the same idea could anyone try to post the few lines that would
actually parse an xml file, with non ascii chars, with minidom
(parseString i guess).
The parser determines the encoding of the file from the ?xml..? line. E.g.
if your file is encoded in utf-8, add the line
?xml version=1.0 encoding=utf-8?
at the top of it, if it's not already present.
The parser will then decode everything into unicode strings - all TextNodes,
attributes etc. should be unicode strings.
When writing the manipulated DOM back to disk, use toxml() which has an
encoding argument.
Then convert a string grabbed from the net so parts of it can be
inserted in that dom object into new nodes or existing nodes.
And finally write that dom object back to a file in a way it can be used
again later with the same script..
Just insert the unicode strings.
I've been trying to do that for a few days with no luck..
I can do each separate part of the job, not that i'm quite sure how i
decode/encode stuff in there, but as soon as i try to do everything at
the same time i get encoding errors thrown all the time..
3. in order to help me understand what's going on when doing
encodes/decodes could you please tell me if in the following example, s
and backToBytes are actually the same thing ??
s = hello normal string
u = unicode( s, utf-8 )
backToBytes = u.encode( utf-8 )
i knwo they both are bytestrings but i doubt they have actually the same
content..
Why not try it yourself?
hello normal string is just US-ASCII. The utf-8 encoded version of the
unicode string uhello normal string will be identical to the ASCII byte
string hello normal string.
4. I've also tried to set the default encoding of python for my script
using the sys.setdefaultencoding('utf-8') but it keeps telling me that
this module does not have that method.. i'm left no choice but to edit
the site.py file manually to change ascii to utf-8, but i won't be
able to do that on the client computers so..
Anyways i don't know if it would help my script at all..
There was just recently a discussing on setdefaultencoding() on various
pythonistic blogs, e.g.
http://blog.ianbicking.org/python-unicode-doesnt-really-suck.html
any help will be greatly appreciated
thx
Marc
--
Benjamin Niemann
Email: pink at odahoda dot de
WWW: http://www.odahoda.de/
--
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Re: Making a timebomb
[EMAIL PROTECTED] wrote: I have a server that right now runs infinitely. I'd like to make it die after some amount of time. I was thinking of having a timebomb thread that starts when the server starts. The timebomb sits, and sleeps for the specified timeout period (e.g., 5 hours), then does something to make the main thread terminate. But I'm too inexperienced to figure out what that thing is. Any suggestions? class TimeBomb( threading.Thread ): def run(self): timeout = 5 * 60 * 60 #-- 3 hours time.sleep( timeout ) MakeTheRestOfTheStuffDie() class MyServer: def __init__(self): TimeBomb().run() serve() Unfortunately you can raise an exception in another thread. You could tell tell main thread to terminate by setting a flag that is polled by the main thread. You could also try to send a signal to yourself, but I'm not sure what will happen then... -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Reliable destruction
[EMAIL PROTECTED] wrote: Hello, I have a class measurement representing a physical measurement. Different objects in this class represent laboratory equipment, which might raise an exception (e.g. overtemperature). In any case the equipment has to be switched off after the experiment, since if a power supply stays in the on state for a prolonged time equipment may be destroyed. Switching off is done by invoking the destructors of the instruments. My measurement looks like this: class measurement: def __init__(self): self.setup() self.run() def setup(self): self.powerSupply=apparate.PowerSupply() self.magnet=apparate.magnet() # Exception(Communication Error) self.thermo=apparate.thermometer() # some 5 more instruments def run(): for i in range(100) self.powerSupply.setCurrent(i) # Exception(Overcurrent) self.magnet.setField(0.5*i) Different measurements are executed in a script which might run overnight: If one measurement raises an exception the next one might still work and I don't want to loose the results from the following experiments. try: measurement() except: pass try: measurement2() except: pass An exception might be thrown anywhere in init or run if e.g. the PowerSupply overheats. Maybe an asynchronous event might happen, too (user interrupt with ^C but I might live without that if it is impossible to handle) My questions are: 1) under normal conditions (no exceptions) is there a guarantee, that __del__ of all instruments is called at the end of measurement()? 2) if an exception is thrown, will all instruments be deleted if the error occurs in run() ? (only the instruments already initialized if the error occurs in setup() )? I am using CPython (on WinXP) and there are no reference cycles between the instruments. I have to stress again that a reliable finalization is important and cannot wait until the interpreter shuts down. I have tried this and it seems to work but this is of course no guarantee. I would suggest an explicit tearDown() method try: m = measurement() try: m.setup() m.run() finally: m.tearDown() except KeyboardInterrupt: # user pressed ctrl-C print ***BREAK sys.exit(1) except: # you should at least log the exception for later debugging traceback.print_exc() and remove the calls to setup() and run() from the constructor. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Reliable destruction
[EMAIL PROTECTED] wrote: Hello Benjamin, What would happen if an exception was thrown in the middle of setup()? tearDown could not handle this case without having a list of the objects already constructed (Or I would have to rely on the automatic call to __del__, if it is reliable). class measurement: def __init__(self): self.powerSupply = None ... def setup(self): self.powerSupply=apparate.PowerSupply() ... def tearDown(self): if self.powerSupply is not None: try: self.powerSupply.tearDown() except: # Exception in powerSupply.tearDown() should not stop # the following tearDown()s from being executed traceback.print_exc() ... There is still some problem: Imagine a communication error in run() which would cause del to fail on the instrument. Not really sure, if I understand what you mean? Does my tearDown() above covers this? Anyway, I think this case is still more difficult to handle. Reliable, fail-safe software *is* hard to design and implement, that's for sure.. Be happy that it's just a power supply that could overheat and not the core of a nuclear power plant. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Art of Unit Testing
Christoph Zwerschke wrote: Benjamin Niemann wrote: Some (many?) people don't like the unittest module, because it is not very pythonic - nothing to wonder as it has its root in the Java world. That's probably one of the reasons why there are other (more pythonic) unittesting frameworks for Python out there. So I think it would have been better that unittest had been named PUnit to make clear that it is a JUnit port and to allow a more pythonic testing framework to be added to the Python's standard lib. It was called PyUnit before it was integrated into the stdlib. Dunno why it was renamed... -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Art of Unit Testing
Michael Hoffman wrote: Benjamin Niemann wrote: Christoph Zwerschke wrote: Benjamin Niemann wrote: Some (many?) people don't like the unittest module, because it is not very pythonic - nothing to wonder as it has its root in the Java world. That's probably one of the reasons why there are other (more pythonic) unittesting frameworks for Python out there. So I think it would have been better that unittest had been named PUnit to make clear that it is a JUnit port and to allow a more pythonic testing framework to be added to the Python's standard lib. It was called PyUnit before it was integrated into the stdlib. Dunno why it was renamed... unittest describes exactly what it does. pyunit says that it is in Python (duh), and that it has something to do with units, which could be a whole number of things. XUnit (with X being the preferred prefix for the programming language) is a common and wellknown name for a certain kind of unittesting framework. Of course there are some people around who know what unittesting is but never heard of JUnit and it decendents. But a quick textsearch on the TOC of the library reference would reveal it. Anyway, it too late now. I'm thankful that logging is called logging as well, rather than log4py. If someone is heavily using log4j and thinks about moving to Python, she will be happy to see that her preferred logging API is available for Python without even leaving the TOC of the library reference. log4X is a similar case as XUnit. (Is logging an implementation of the log4X API? Never used log4X...) -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: trying to parse non valid html documents with HTMLParser
Steve M wrote: You were right, the HTMLParser of htmllib is more permissive. He just ignores the bad tags ! The HTMLParser on my distribution is a she. But then again, I am using ActivePython on Windows... Although building parsers is for some strange reason one of my favourite programming adventures, I do not have such a personal relationship with my classes ;) -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: trying to parse non valid html documents with HTMLParser
florent wrote: I'm trying to parse html documents from the web, using the HTMLParser class of the HTMLParser module (python 2.3), but some web documents are not fully valids. Some?? Most of them :( When the parser finds an invalid tag, he raises an exception. Then it seems impossible to resume the parsing just after where the exception was raised. I'd like to continue parsing an html document even if an invalid tag was found. Is it possible to do this ? AFAIK not with HTMLParser or htmllib. You might try (if you haven't done yet) htmllib and see, which parser is more forgiving. You might pipe the document through an external tool like HTML Tidy http://www.w3.org/People/Raggett/tidy/ before you feed it into HTMLParser. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Art of Unit Testing
Christoph Zwerschke wrote: Thanks for the link, Grig. I wasn't aware of the py lib so far. The possibility to create fixtures at the three different scopes is exactly what I was looking for. Anyway, I think it would be nice to have that feature in the standard lib unittest as well. It should not be too hard to add setUpOnce and tearDownOnce methods in addition to setUp and tearDown. Actually, I am wondering that there doesn't seem to be any development progress since unittest was included in the standard lib of Python 2.1 in August 2001. I had expected that such an important module would be continually improved and maintained. How come? So few people using unit tests? Or do most people write their own testing code or use py.test? Or because it is already close to perfection (at least in what it is intended to do). The unittest module is a 'port' of the JUnit framework for Java which has a certain wellknown API and semantics. The same API is available for many other languages, so it is probably a good idea to stick with it in order to make people coming from other language feel more comfortable with Python. Some (many?) people don't like the unittest module, because it is not very pythonic - nothing to wonder as it has its root in the Java world. That's probably one of the reasons why there are other (more pythonic) unittesting frameworks for Python out there. I prefer to use unittest (because this was the API the textbook was using that introduced me to this topic) and I also had the problem of heavy setup costs. I deal with it by using a script around my testsuite (instead of calling just unittest.main()) that does the setup/teardown of the environment. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: python SMTP server
Cliff Wells wrote: On Sun, 2005-07-31 at 13:14 +0200, Benjamin Niemann wrote: But you should be aware of the fact that (if you send mail from a dialup machine without going through a relay server) your mails will quickly be marked as spam - I hope you do not intend to send spam... Yah, Postfix on my servers uses several dnsbl's which automatically reject home users (unless they authenticate first). Even if this isn't the case for the majority of SMTP servers today I expect it won't be long before it is. As an aside, I will say that many SMTP servers that service home users (i.e. Comcast, et al) limit the amount of mail that you can send within a defined period. Or completely block outgoing traffic on port 25 except to their own relay... By using a local SMTP server to proxy, your app can queue up a large amount of mail in a much shorter period. It won't necessarily go out any faster, but at least your app won't be tied up waiting for the mail to be accepted. So there is perhaps one useful (beyond learning and fun) application for using a local SMTP server. It would be interesting what the intention of the OP is. I just stumpled upon a similar problem. The prog I'm currently working on has a function to report crashes back to me. Originally these reports where sent by mail - no problem on UNIX/Linux hosts where you can assume to have a working MDA on localhost. But what to do on Windows systems?!? Ask for a SMTP server during installation? Confusing as the program itself is totally unrelated to email. In this case you _could_ deliver the mail directly to my MX host... But instead of this I installed a small CGI on my website that sends the mails to me and gets the data via HTTP POST from my app. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: python SMTP server
Cliff Wells wrote: On Mon, 2005-08-01 at 12:28 +0200, Benjamin Niemann wrote: Cliff Wells wrote: [snip] By using a local SMTP server to proxy, your app can queue up a large amount of mail in a much shorter period. It won't necessarily go out any faster, but at least your app won't be tied up waiting for the mail to be accepted. So there is perhaps one useful (beyond learning and fun) application for using a local SMTP server. It would be interesting what the intention of the OP is. I just stumpled upon a similar problem. The prog I'm currently working on has a function to report crashes back to me. Originally these reports where sent by mail - no problem on UNIX/Linux hosts where you can assume to have a working MDA on localhost. But what to do on Windows systems?!? Ask for a SMTP server during installation? Confusing as the program itself is totally unrelated to email. In this case you _could_ deliver the mail directly to my MX host... But instead of this I installed a small CGI on my website that sends the mails to me and gets the data via HTTP POST from my app. You can also use port redirection to bypass this sort of thing. Send on port 10025 instead and direct your MTA to listen on both ports. This would still be problematic with company firewall that block everything but a handful of ports. Port 80 is still one of the safest bets. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: python SMTP server
Fernando M. wrote:
Hi,
i made a test with smtplib module a few days ago, for sending mails,
and i was wondering if there's another module for running an SMTP
server, so i could make a standalone script for sending mails without
using an external SMTP server.
I've been searching but i'm not sure if there are modules for it, or
anything.
Which ones are my options?
An SMTP server is (simplified) a program that listens on port 25 for
incoming mails.
What you probably want to do is:
Do a DNS query for the recipent's domain and use smtplib to connect to the
server specified in the MX record. There was a module for DNS querie (not
in Python's stdlib), but I forgot how it was called or where you could find
it (try the Vaults of Parnassus or PyPI).
Or you may use an external tool like 'dig' ('dig mx DOMAIN').
But you should be aware of the fact that (if you send mail from a dialup
machine without going through a relay server) your mails will quickly be
marked as spam - I hope you do not intend to send spam...
--
Benjamin Niemann
Email: pink at odahoda dot de
WWW: http://www.odahoda.de/
--
http://mail.python.org/mailman/listinfo/python-list
Re: Getting TypeError in Changing file permissions
Pranav Bagora wrote: Hello , i am trying to change mode of files using the os.chmod()function. But i am getting an error os.chmod(outfile,0700) TypeError: coercing to Unicode: need string or buffer, file found Looks as if your are using a file object (that you got from an open() call) as the first parameter. What you need is a string with the path to the file. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Difference between and '
[EMAIL PROTECTED] wrote: Hi, Can someone tell me the difference between single quote and double quote? There is none. Except that in a double quoted string, single quotes don't have to be escaped and vice versa, sometimes one of the two forms saves you some backslashes: That's my house == 'That\'s my house' You say: \Hello\ == 'You say: Hello' -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: dictionary as property
Thanos Tsouanas wrote:
Hello.
(How) can I have a class property d, such that d['foo'] = 'bar' will run
a certain function of the class with 'foo' and 'bar' as it's arguments?
I think you mean:
class A:
def __init__(self):
self.d = {}
def dict_change(self, key, value):
print key, value
a = A()
a.d['foo'] = 'bar'
-- foo bar
'a' only has a reference to 'd', it won't know, who has a copy of this
reference and what done to it.
What you could create, is a wrapper around 'd', that passes __getitem__,
__setitem__ and every other required method to the underlying dict and call
the appropriate hook method of A
class WrappedDict:
def __init__(self, owner, d):
self.owner = owner
self.d = d
def __setitem__(self, key, value):
self.owner.dict_changed(key, value)
self.d[key] = value
def __getitem(self, key):
return self.d[key]
And in A.__init__
self.d = WrappedDict(self, {})
You may also subclass WrappedDict from dict...
--
Benjamin Niemann
Email: pink at odahoda dot de
WWW: http://www.odahoda.de/
--
http://mail.python.org/mailman/listinfo/python-list
Re: Python Regular Expressions: re.sub(regex, replacement, subject)
Vibha Tripathi wrote: Hi Folks, I put a Regular Expression question on this list a couple days ago. I would like to rephrase my question as below: In the Python re.sub(regex, replacement, subject) method/function, I need the second argument 'replacement' to be another regular expression ( not a string) . So when I find a 'certain kind of string' in the subject, I can replace it with 'another kind of string' ( not a predefined string ). Note that the 'replacement' may depend on what exact string is found as a result of match with the first argument 'regex'. Do mean 'backreferences'? re.sub(rthis(\d+)that, rthat\1this, this12that foo13bar) 'that12this foo13bar' Note that the replacement string rthat\1this is not a regular expression, it has completely different semantics as described in the docs. (Just guessing: are you coming from perl? rxxx is not a regular expression in Python, like /xxx/ in perl. It's is just an ordinary string where backslashes are not interpreted by the parser, e.g. r\x == \\x. Using r when working with the re module is not required but pretty useful, because re has it's own rules for backslash handling). For more details see the docs for re.sub(): http://docs.python.org/lib/node114.html -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Lisp development with macros faster than Python development?..
[EMAIL PROTECTED] wrote: I've been reading the beloved Paul Graham's Hackers and Painters. He claims he developed a web app at light speed using Lisp and lots of macros. It got me curious if Lisp is inherently faster to develop complex apps in. It would seem if you could create your own language in Lisp using macros that that would be quite an advantage I realize that Python has operator overloading and OOP so I'm not sure. Any ideas? Any *evidence* one way or another? If that means that I have to learn a new programming language for every program I'd like to apply a minor fix/customization to: not a good idea. Probably not just for the casual hacker like me, but also for the maintainance phase of a project, when the former lead gurus lost interest and/or employment. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Existance of of variable
George Sakkis wrote: Hi Josiah, Hello. I am very new to Python, and have been unable to figure out how to check if a variable exists or not. In the following code I have made a kludge that works, but I think that it would be clearer to check if closest exists and not have to initialize it in the first place. How is that check done? The following code finds the closest place to a position and rejects places that are too far away. dist = 1e9 closest = -1 for n,p in galaxy.places.iteritems(): dif = p.pos - pos len = dif.len() if len dist and len 10.0/self.zoom: dist = len closest = p if closest != -1: self.sel = [closest.name] I would write it like this: def setClosest(self, pos, galaxy): minDist, closestPlace = min([((place.pos-pos).len(), place) for place in galaxy.places.itervalues()]) if minDist 10.0/self.zoom: self.sel = [closestPlace.name] else: raise RuntimeError(No place close enough) A galaxy can be pretty big and contain a lot of places ;) You'll easily run out of memory, if you try to build a list of (dist, place) tuples. Better use the generator syntax (requires python 2.4): minDist, closestPlace = min(((place.pos-pos).len(), place) for place in galaxy.places.itervalues()) -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: nested lists - utter newbie
[EMAIL PROTECTED] wrote:
Hi,
why is this possible -
b = [1,2,3]
b[2] = b
b
[1,2,[...]]
b[2]
[1,2,[...]]
b[2][2][2][2][2]
[1,2,[...]]
but this is not -
x = [1,2,x]
Traceback (most recent call last):
File stdin, line 1, in ?
NameError: name 'x' is not defined
Because the right hand side ('[1,2,x]') is evaluated *before* the value is
bound to the name 'x' - and at this point there is obviously no name 'x'
defined.
--
Benjamin Niemann
Email: pink at odahoda dot de
WWW: http://www.odahoda.de/
--
http://mail.python.org/mailman/listinfo/python-list
Re: Request for help on naming conventions
Steven D'Aprano wrote: Are there any useful naming conventions for modules, classes and functions? For instance, should I name functions as verbs and classes as nouns? eg class Transformer(): pass def transform(): do_stuff What about the module name? transformations.py or transform.py? You probably want to read the PEP 8, Style Guide for Python Code: http://www.python.org/peps/pep-0008.html What do people do with their own code? Do folks find that being consistent helps them remember what is what, or do you name objects whatever feels right at the time? Naming convention are mostly a matter of personal taste (unless you are working in a larger team, where there are some official conventions that must be followed). So I would say the 'feels right' is the most important factor. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Walking through a mysql db
Jeff Elkins wrote: I'm writing a small wxpython app to display and update a dataset. So far, I get the first record for display: try: cursor = conn.cursor () cursor.execute (SELECT * FROM dataset) item = cursor.fetchone () Now, how do I step through the dataset one row at a time? My form has 'next' and 'back' buttons, and I'd like them to step forward or back, fetching the appropriate row in the table. I've tried setting cursor.rownumber by incrementing it prior to the fetchone() w/o effect. You could either execute N-1 fetchone()s before you fetch the Nth dataset (with N starting at 1) or use the 'LIMIT' feature of MySQL: cursor.execute (SELECT * FROM dataset LIMIT %s,1, n) where n is the index of the requested dataset (starting at 0) -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: write html-headers (utf-8)
db wrote: Hello all, I hope this is the correct newsgroup for this question. Does anybody know how I can write a html-header with python(cgi)? The problem is, I have a few html templates in which I have a header e.g: !DOCTYPE HTML PUBLIC -//W3C//DTD HTML 4.01 Transitional//EN http://www.w3.org/TR/html4/strict.dtd; html head meta http-equiv=Content-Type content=text/html; charset=UTF-8 In this template I write a few Mysql variables. Those variable often have german characters. This characters (Gösing in stead of Gösing). The german characters in the html template are shown correctly. If I change the character encoding with the browser to utf-8, all the characters are shown correctly. As you can see, I put in the header of the html template that the encoding is UTF-8, the browser still shows windows ISO-8859-15. Can I write the header with python so the browser uses the utf-8 encoding? My hosting providor uses fedora core 2, Python 2.2.3, MySQLdb. Mysql 3.23.58 I googled for hours, but I can't find the answer. I hope ypu can help me. Does your browser send a Content-Type HTTP header (don't confuse this with the HTML head part)? If it does and it specifies a charset, this will override your meta http-equiv. Often iso-8859-1 is the default charset for the Content-Type header. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: Suggesting methods with similar names
[EMAIL PROTECTED] wrote:
I have a class Surface with many methods. Working in the interactive
window I receive an error like this when I write the wrong method name:
table.addGlas()
Traceback (most recent call last):
File stdin, line 1, in ?
AttributeError: 'Surface' object has no attribute 'addGlas'
Is it possibile to make the object give a better answer: a short list
of few method names similar to the one I've misspelled?
I've found some modules with phonetic algorithms like soundex,
metaphone, etc, for example here:
http://sourceforge.net/projects/advas/
I can produce the list of method names with this:
toRemove = __delattr__ __dict__ __getattribute__ __module__ __new__
__reduce__ __copy__ __reduce_ex__ __setattr__ __slot__
__weakref__ __str__ __class__ __doc__.split()
methods = sorted( set(dir(Surface)).difference(toRemove) )
The problem is calling the phonetic algorithm to show a ranked list of
the 2-4 method names most similar to the wrong one called. I don't know
if this problem requires a change in the python shell, or in the
metaclass of that Surface class, etc.
And in the end maybe this functionality (inspired by a similar
Mathematica one) is already inside IPython :-]
You could achieve this by overriding __getattribute__ (untested):
def __getattribute__(self, name):
try:
object.__getattribute__(self, name) # or whatever is your superclass
# or use super(), but I would have to lookup the syntax and
# breakfast is waiting ;)
except AttributeError:
# find similar attributes
suggestions =
raise AttributeError('Surface' object has no attribute '%s'. Did you
mean %s? % (name, suggestions))
I leave it to the experts to wrap this into a generic metaclass, decorator
etc. ;)
--
Benjamin Niemann
Email: pink at odahoda dot de
WWW: http://www.odahoda.de/
--
http://mail.python.org/mailman/listinfo/python-list
Re: IronPython 0.7 released!
Ville Vainio wrote: Robin == Robin Becker [EMAIL PROTECTED] writes: Robin well that's nice, but I don't do blogs and certainly don't You don't need to do much - just go to planetpython.org Or check out the Daily Python URL (http://www.pythonware.com/daily/) which has a pretty high signal to noise ratio. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: IronPython 0.7 released!
Robin Becker wrote: Do Re Mi chel La Si Do wrote: Hi ! I am curious : 1)I can't download the file (error in the GotDotNet system). 2) On http://ironpython.com, there are no new version I'm also a bit puzzled that www.ironpython.com has no mention of this release. Curious that J Hugunin didn't announce it himself. Jim Hugunin announced it himself in a keynote at PyCon. You can read a lot about it on Python centric blogs - just one example: http://www.postneo.com/2005/03/23/keynote-ironpython -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
Re: string join() method
Derek Basch wrote: Can anyone tell me why this CGI code outputs a blank page? self.output = [] self.setContentType(text/plain) ascii_temp.seek(0) self.output.extend(ascii_temp.read()) print ''.join(self.output) def setContentType(self, type=text/xml): self.output.extend([Content-type: , type, \n\r]) - but this code works?: - self.output = [] self.setContentType(text/plain) print ''.join(self.output) ascii_temp.seek(0) print ascii_temp.read() def setContentType(self, type=text/xml): self.output.extend([Content-type: , type, \n\r]) - [snip] First thing: HTTP header lines must be terminated by \r\n not \n\r. The headers are terminated by another \r\n. I'm not sure (but I would bet an Euro or two that it does), but perhaps the webserver sanitizes the output of CGI script and converts plain \n into \r\n - if not then you shouldn't use print to output the headers, because it only outputs non-HTTPish \n. The output of your first script is --- Content-type: text/plain\r\n Allele... --- whereas the second script outputs --- Content-type: text/plain\r\n \n Allele... --- The (required) \n - that should also be an \r\n - seperating the headers from the content is added by the first print. -- Benjamin Niemann Email: pink at odahoda dot de WWW: http://www.odahoda.de/ -- http://mail.python.org/mailman/listinfo/python-list
