Re: Obtaining user information
On 10Dec2011 08:43, Hans Mulder wrote: | On 10/12/11 02:44:48, Tim Chase wrote: | >Currently I can get the currently-logged-in-userid via getpass.getuser() | >which would yield something like "tchase". | > | >Is there a cross-platform way to get the full username (such as from the | >GECOS field of /etc/passed or via something like NetUserGetInfo on Win32 | >so I'd get "Tim Chase" instead? | | How about: | pwd.getpwuid(os.getuid()).pw_gecos | This will give you the GECOS field of /etc/passed. | I'd assume it contains "Tim Chase" for your account. Up to a comma is the convention. Eg "Cameron Simpson, x2983". -- Cameron Simpson DoD#743 http://www.cskk.ezoshosting.com/cs/ Microsoft - where "cross platform" means "runs in both Win95 and WinNT". - Andy Newman -- http://mail.python.org/mailman/listinfo/python-list
Re: Buffering of sys.stdout and sys.stderr in python3 (and documentation)
Hi Terry, > The difference from 2.x should be in What's New in 3.0, except that the > new i/o module is in 2.6, so it was not exactly new. The io module existed in 2.6, but it was not used by default for standard output and standard error. The only mention of this in "What's New in 3.0" is in the section marked for changes that were already in 2.6 (which is wrong in this case), and it notes only that io.TextIOWrapper is now used, but not what implications that has for its behaviour and backward compatibility. > You might be able > to find more inhttp://python.org/dev/peps/pep-3116/ I skimmed through it but couldn't find anything relevant. It seems more "advanced" and implementation-focussed. > > You *should* be able to find sufficient info in the 3.x docs. If, after > you get other responses (or not), you think the docs need upgrading, > open an issue on the tracker at bugs.python.org with suggestions as > specific as possible, including changed or new lines of text based on > your experience and experiments. OK, I'll do that if nobody points me at some existing docs here. Regards, Geoff Bache -- http://mail.python.org/mailman/listinfo/python-list
Re: Python 2 or 3
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Steven D'Aprano wrote: > RHEL supports Python 3, it just doesn't provide Python 3. True, but as you say later, the only method is to recompile. So, if I want to use Python 3 in a production environment like RHEL, I need: - A development environment similar to production (e.g. if I use RHEL 5 in production, I need at least a CentOS 5.x); - Compile Python 3 in a development environment; - Write the python app; - Release a *huge* package to install. The only bright side is to freeze version of Python and the libraries, but every update (e.g. bug fixing on a library) is by hand > When installing, don't use "make install", as that will replace the > system Python, instead use "make altinstall". Good, I didn't know this option > Then the command "python" > will still refer to the system Python (probably Python 2.4 or 2.5?), and > "python3" should refer to Python 3.x. RHEL (and CentOS) 5.x use Python 2.4 > You shouldn't be learning programming on a production server :) Of course, but if I want to use an application written in Python 3 on a production environment which doesn't support it, I have to prepare at least a development environment similar to production (ok, ok, with a VM is simple, but I need to track the exception) Enrico P.S. an alternative may be cx_freeze, but I don't know exactly hot it works P.P.S. I'm boring, but I would like my point of view because I've found precisely in this case -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.11 (GNU/Linux) iQEcBAEBAgAGBQJO40dHAAoJED3SMOGZLYdYIPoH/1J6OljjCJQnmR/uwjEFCrHy TEMpfKodD40gL7lOZLMHnpJrs+Ct2Vo/1+mtAIi+vZ6rkhFG50ykBJMAlMgXkCjt I6fkp9YLKmFX9OjRuJ9qE+2P5PliyNDPKVljyfaXMhalbrtHnn7mrL9524TzhcoG +Ape1U9MPTu3naVULKWK0FjGa/RwhbSOdDOKX2IBmRHFEgtf3dZJ2xNYXUJnhnT8 fbfD87ykXyyVg6LS8c14PPeWnpFeeZBQappjoHg9+XZd8/Y1uH1NuP7k4cepzJB2 Car4lucChW9+llM4mz1BADQZuo4J1v71K5DR8mVXyM2usUlNWelkgR6GVWUmXE0= =trwj -END PGP SIGNATURE- -- http://mail.python.org/mailman/listinfo/python-list
WeakValueDict and threadsafety
I am using a WeakValueDict in a way that is nearly identical to the example at the end of http://docs.python.org/library/weakref.html?highlight=weakref#example , where "an application can use objects IDs to retrieve objects that it has seen before. The IDs of the objects can then be used in other data structures without forcing the objects to remain alive, but the objects can still be retrieved by ID if they do." My program is multithreaded, so I added the necessary check for liveliness that was discussed at http://docs.python.org/library/weakref.html?highlight=weakref#weak-reference-objects . Basically, I have: import threading import weakref registry = weakref.WeakValueDictionary() reglock = threading.Lock() def get_data(oid): with reglock: data = registry.get(oid, None) if data is None: data = make_data() registry[id(data)] = data return data I'm concerned that this is not actually thread-safe. When I no longer hold strong references to an instance of data, at some point the garbage collector will kick in and remove that entry from my registry. How can I ensure the garbage collection process does not modify the registry while I'm holding the lock? Thanks, Darren -- http://mail.python.org/mailman/listinfo/python-list
Re: Obtaining user information
On 12/10/11 01:37, Cameron Simpson wrote:
On 09Dec2011 19:44, Tim Chase wrote:
| Currently I can get the currently-logged-in-userid via
| getpass.getuser() which would yield something like "tchase".
_If_ you're on a terminal. _And_ that's exactly what you want.
Personally I need to the name of geteuid() or getuid() more often.
yes, it deals with emailing so the local userid and full-name are
what I want.
| Is there a cross-platform way to get the full username (such as from
| the GECOS field of /etc/passed or via something like NetUserGetInfo
| on Win32 so I'd get "Tim Chase" instead?
Hmm. Doesn't windows have a posix layer?
pwd.getpwnam(os.getuid())[4].split(',')[0]
is the best I've got. ANd it probably doesn't work in Windows:-(
well, that's a more readable version of my hand-crafted opening
of /etc/passwd and parsing by hand, so thanks! As you mention,
the pwd module isn't available on Win32 so I still have to branch
my code. I found Tim Golden's suggestion in a comment on
ActiveState[1] that gave this one-liner for Win32:
win32net.NetUserGetInfo (win32net.NetGetAnyDCName (),
win32api.GetUserName (), 1)
By changing the "1" to a "20", one of the returned key/value
pairs was "full_name" and the username, so my code currently reads:
def get_user_info():
"Return (userid, username) e.g. ('jsmith', 'John Smith')"
userid = username = getpass.getuser()
if sys.platform.lower().startswith("win"):
try:
import win32net, win32api
USER_INFO_2 = 2
username = win32net.NetUserGetInfo(
win32net.NetGetAnyDCName(),
win32api.GetUserName(),
USER_INFO_2,
)["full_name"] or username
except ImportError:
pass # no win32* module, so default to userid
else:
import pwd
username = pwd.getpwnam(userid).pw_gecos.split(',',1)[0]
return userid, username
It only addresses Win32 and Posix, but that's what I need for
now. Thanks again.
-tkc
[1]
http://code.activestate.com/recipes/66314-get-user-info-on-windows-for-current-user/
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Re: I love the decorator in Python!!!
Just wrap the exec() to spawn for fun. -- http://mail.python.org/mailman/listinfo/python-list
Re: I love the decorator in Python!!!
Wrap functions to yield is somewhat like a sub-threading in Erlang. -- http://mail.python.org/mailman/listinfo/python-list
Re: WeakValueDict and threadsafety
Darren Dale wrote: > I'm concerned that this is not actually thread-safe. When I no longer > hold strong references to an instance of data, at some point the > garbage collector will kick in and remove that entry from my registry. > How can I ensure the garbage collection process does not modify the > registry while I'm holding the lock? You can't, but it shouldn't matter. So long as you have a strong reference in 'data' that particular object will continue to exist. Other entries in 'registry' might disappear while you are holding your lock but that shouldn't matter to you. What is concerning though is that you are using `id(data)` as the key and then presumably storing that separately as your `oid` value. If the lifetime of the value stored as `oid` exceeds the lifetime of the strong references to `data` then you might get a new data value created with the same id as some previous value. In other words I think there's a problem here, but nothing to do with the lock. -- Duncan Booth -- http://mail.python.org/mailman/listinfo/python-list
Re: how to test attribute existence of feedparser objects
On Thursday 2011 December 08 01:34, HansPeter wrote:
> Hi,
>
> While using the feedparser library for downloading RSS feeds some of
> the blog entries seem to have no title.
>
> File "build\bdist.win32\egg\feedparser.py", line 382, in __getattr__
> AttributeError: object has no attribute 'title'
>
> Is there a way to test the existence of an attribute?
>
>From the Fine Manual for feedparser 5.1:
Testing for Existence¶
Feeds in the real world may be missing elements, even elements that are
required by the specification. You should always test for the existence of an
element before getting its value. Never assume an element is present.
Use standard Python dictionary functions such as has_key to test whether an
element exists.
Testing if elements are present¶
>>> import feedparser
>>> d = feedparser.parse('http://feedparser.org/docs/examples/atom10.xml')
>>> d.feed.has_key('title')
True
>>> d.feed.has_key('ttl')
False
>>> d.feed.get('title', 'No title')
u'Sample feed'
>>> d.feed.get('ttl', 60)
60
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Re: how to test attribute existence of feedparser objects
On Sat, 10 Dec 2011 09:19:31 -0800, xDog Walker wrote:
> Use standard Python dictionary functions such as has_key to test whether
> an element exists.
Idiomatic Python code today no longer uses has_key.
# Was:
d.feed.has_key('title')
# Now preferred
'title' in d.feed
--
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Re: Multiprocessing bug, is information ever omitted from a traceback?
On Dec 9, 9:00 pm, Terry Reedy wrote: > On 12/9/2011 6:14 PM, John Ladasky wrote: > > >http://groups.google.com/group/comp.lang.python/browse_frm/thread/751... > > > I'm programming in Python 2.6 on Ubuntu Linux 10.10, if it matters. > > It might, as many bugs have been fixed since. > Can you try the same code with the most recent 2.x release, 2.7.2? > Do you have working and non-working code that you can publicly release? > Can you reduce the size and dependencies so the examples are closer to > 'small' than 'large'? And in any case, self-contained? > > In my first response, I said you might have found a bug. A bogus > exception message qualifies. But to do much, we need minimal good/bad > examples that run or not on a current release (2.7.2 or 3.2.2). > > -- > Terry Jan Reedy All right, Terry, you've convinced me to look. This will take some time. I'll hack away at the two versions of my 500-line programs, until I have a minimal example. Why did you specify Python 2.7.2, instead of the 2.7.6 version that is being offered to me by Ubuntu Software Center? Does it matter? -- http://mail.python.org/mailman/listinfo/python-list
Re: WeakValueDict and threadsafety
On Dec 10, 11:19 am, Duncan Booth
wrote:
> Darren Dale wrote:
> > I'm concerned that this is not actually thread-safe. When I no longer
> > hold strong references to an instance of data, at some point the
> > garbage collector will kick in and remove that entry from my registry.
> > How can I ensure the garbage collection process does not modify the
> > registry while I'm holding the lock?
>
> You can't, but it shouldn't matter.
>
> So long as you have a strong reference in 'data' that particular object
> will continue to exist. Other entries in 'registry' might disappear while
> you are holding your lock but that shouldn't matter to you.
>
> What is concerning though is that you are using `id(data)` as the key and
> then presumably storing that separately as your `oid` value. If the
> lifetime of the value stored as `oid` exceeds the lifetime of the strong
> references to `data` then you might get a new data value created with the
> same id as some previous value.
>
> In other words I think there's a problem here, but nothing to do with the
> lock.
Thank you for the considered response. In reality, I am not using
id(data). I took that from the example in the documentation at
python.org in order to illustrate the basic approach, but it looks
like I introduced an error in the code. It should read:
def get_data(oid):
with reglock:
data = registry.get(oid, None)
if data is None:
data = make_data(oid)
registry[oid] = data
return data
Does that look better? I am actually working on the h5py project
(bindings to hdf5), and the oid is an hdf5 object identifier.
make_data(oid) creates a proxy object that stores a strong reference
to oid.
My concern is that the garbage collector is modifying the dictionary
underlying WeakValueDictionary at the same time that my multithreaded
code is trying to access it, producing a race condition. This morning
I wrote a synchronized version of WeakValueDictionary (actually
implemented in cython):
class _Registry:
def __cinit__(self):
def remove(wr, selfref=ref(self)):
self = selfref()
if self is not None:
self._delitem(wr.key)
self._remove = remove
self._data = {}
self._lock = FastRLock()
__hash__ = None
def __setitem__(self, key, val):
with self._lock:
self._data[key] = KeyedRef(val, self._remove, key)
def _delitem(self, key):
with self._lock:
del self._data[key]
def get(self, key, default=None):
with self._lock:
try:
wr = self._data[key]
except KeyError:
return default
else:
o = wr()
if o is None:
return default
else:
return o
Now that I am using this _Registry class instead of
WeakValueDictionary, my test scripts and my actual program are no
longer producing segfaults.
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Re: Multiprocessing bug, is information ever omitted from a traceback?
On 12/10/2011 11:53 AM, John Ladasky wrote: > Why did you specify Python 2.7.2, instead of the 2.7.6 version that is > being offered to me by Ubuntu Software Center? Does it matter? There is no Python 2.7.6. I think you have it confused with the version 2.7.2-6. If I'm not mistaken, that appended 6 has to do with packaging and nothing at all to do with the software itself. -- CPython 3.2.2 | Windows NT 6.1.7601.17640 | Thunderbird 7.0 -- http://mail.python.org/mailman/listinfo/python-list
Re: WeakValueDict and threadsafety
On Sunday, December 11, 2011 1:56:38 AM UTC+8, Darren Dale wrote:
> On Dec 10, 11:19 am, Duncan Booth
> wrote:
> > Darren Dale wrote:
> > > I'm concerned that this is not actually thread-safe. When I no longer
> > > hold strong references to an instance of data, at some point the
> > > garbage collector will kick in and remove that entry from my registry.
> > > How can I ensure the garbage collection process does not modify the
> > > registry while I'm holding the lock?
> >
> > You can't, but it shouldn't matter.
> >
> > So long as you have a strong reference in 'data' that particular object
> > will continue to exist. Other entries in 'registry' might disappear while
> > you are holding your lock but that shouldn't matter to you.
> >
> > What is concerning though is that you are using `id(data)` as the key and
> > then presumably storing that separately as your `oid` value. If the
> > lifetime of the value stored as `oid` exceeds the lifetime of the strong
> > references to `data` then you might get a new data value created with the
> > same id as some previous value.
> >
> > In other words I think there's a problem here, but nothing to do with the
> > lock.
>
> Thank you for the considered response. In reality, I am not using
> id(data). I took that from the example in the documentation at
> python.org in order to illustrate the basic approach, but it looks
> like I introduced an error in the code. It should read:
>
> def get_data(oid):
> with reglock:
> data = registry.get(oid, None)
> if data is None:
> data = make_data(oid)
> registry[oid] = data
> return data
>
> Does that look better? I am actually working on the h5py project
> (bindings to hdf5), and the oid is an hdf5 object identifier.
> make_data(oid) creates a proxy object that stores a strong reference
> to oid.
>
> My concern is that the garbage collector is modifying the dictionary
> underlying WeakValueDictionary at the same time that my multithreaded
> code is trying to access it, producing a race condition. This morning
> I wrote a synchronized version of WeakValueDictionary (actually
> implemented in cython):
>
> class _Registry:
>
> def __cinit__(self):
> def remove(wr, selfref=ref(self)):
> self = selfref()
> if self is not None:
> self._delitem(wr.key)
> self._remove = remove
> self._data = {}
> self._lock = FastRLock()
>
> __hash__ = None
>
> def __setitem__(self, key, val):
> with self._lock:
> self._data[key] = KeyedRef(val, self._remove, key)
>
> def _delitem(self, key):
> with self._lock:
> del self._data[key]
>
> def get(self, key, default=None):
> with self._lock:
> try:
> wr = self._data[key]
> except KeyError:
> return default
> else:
> o = wr()
> if o is None:
> return default
> else:
> return o
>
> Now that I am using this _Registry class instead of
> WeakValueDictionary, my test scripts and my actual program are no
> longer producing segfaults.
I'll prefer to get iterators and iterables that can accept a global signal
called a clock to replace these CS mess.
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Re: Multiprocessing bug, is information ever omitted from a traceback?
On Sun, Dec 11, 2011 at 5:38 AM, Andrew Berg wrote: > On 12/10/2011 11:53 AM, John Ladasky wrote: >> Why did you specify Python 2.7.2, instead of the 2.7.6 version that is >> being offered to me by Ubuntu Software Center? Does it matter? > There is no Python 2.7.6. I think you have it confused with the version > 2.7.2-6. If I'm not mistaken, that appended 6 has to do with packaging > and nothing at all to do with the software itself. On 12/9/2011 6:14 PM, John Ladasky wrote: > I'm programming in Python 2.6 on Ubuntu Linux 10.10, if it matters. As with my Ubuntu 10.10 - it's version 2.6.6. (I also altinstalled 3.3 built straight from Mercurial, which is approximately as new a Python as one can have, but that doesn't count.) There's a few differences between 2.6 and 2.7; not usually enough to be concerned about in daily use, but when dealing with weird issues, it helps to have the latest release. ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: Multiprocessing bug, is information ever omitted from a traceback?
On Dec 10, 10:38 am, Andrew Berg wrote: > On 12/10/2011 11:53 AM, John Ladasky wrote:> Why did you specify Python > 2.7.2, instead of the 2.7.6 version that is > > being offered to me by Ubuntu Software Center? Does it matter? > > There is no Python 2.7.6. I think you have it confused with the version > 2.7.2-6. If I'm not mistaken, that appended 6 has to do with packaging > and nothing at all to do with the software itself. > > -- > CPython 3.2.2 | Windows NT 6.1.7601.17640 | Thunderbird 7.0 How annoying, here's how Ubuntu Software Center described it: "Version: 2.7-6 (python2.7)" And here it is in the Synaptic Package Manager: "package: python2.7-minimal, installed version: 2.7-6" At first I considered that this truncated name might be the consequence of a Linux bug. But looking up and down my list of installed software in both Ubuntu Software Center and Synaptic, I can find version names which extend arbitrarily, such as my wxPython installation, for which the version number reads "2.8.11.0-0ubuntu4.1". Now my hypothesis is that someone manually enters the revision numbers into the Linux database, and they made a typo. -- http://mail.python.org/mailman/listinfo/python-list
Re: WeakValueDict and threadsafety
Darren Dale wrote: > On Dec 10, 11:19 am, Duncan Booth > wrote: >> Darren Dale wrote: > def get_data(oid): > with reglock: > data = registry.get(oid, None) > if data is None: > data = make_data(oid) > registry[oid] = data > return data > > Does that look better? I am actually working on the h5py project > (bindings to hdf5), and the oid is an hdf5 object identifier. > make_data(oid) creates a proxy object that stores a strong reference > to oid. Yes, that looks better. > > Now that I am using this _Registry class instead of > WeakValueDictionary, my test scripts and my actual program are no > longer producing segfaults. > I think that so far as multi-thread race conditions are concerned Python usually tries to guarantee that you won't get seg faults. So if you were getting seg faults my guess would be that either you've found a bug in the WeakValueDictionary implementation or you've got a bug in some of your code outside Python. For example if your proxy object has a __del__ method to clean up the object it is proxying then you could be creating a new object with the same oid as one that is in the process of being destroyed (the object disappears from the WeakValueDictionary before the __del__ method is actually called). Without knowing anything about HDF5 I don't know if that's a problem but I could imagine you could end up creating a new proxy object that references something in the HDF5 library which you then destroy as part of cleaning up a previous incarnation of the object but continue to access through the new proxy. -- Duncan Booth http://kupuguy.blogspot.com -- http://mail.python.org/mailman/listinfo/python-list
Re: WeakValueDict and threadsafety
On Dec 10, 2:09 pm, Duncan Booth wrote: > Darren Dale wrote: > > On Dec 10, 11:19 am, Duncan Booth > > wrote: > >> Darren Dale wrote: > > def get_data(oid): > > with reglock: > > data = registry.get(oid, None) > > if data is None: > > data = make_data(oid) > > registry[oid] = data > > return data > > > Does that look better? I am actually working on the h5py project > > (bindings to hdf5), and the oid is an hdf5 object identifier. > > make_data(oid) creates a proxy object that stores a strong reference > > to oid. > > Yes, that looks better. > > > > > Now that I am using this _Registry class instead of > > WeakValueDictionary, my test scripts and my actual program are no > > longer producing segfaults. > > I think that so far as multi-thread race conditions are concerned Python > usually tries to guarantee that you won't get seg faults. So if you were > getting seg faults my guess would be that either you've found a bug in the > WeakValueDictionary implementation or you've got a bug in some of your code > outside Python. Have you seen Alex Martelli's answer at http://stackoverflow.com/questions/3358770/python-dictionary-is-thread-safe ? The way I read that, it seems pretty clear that deleting items from a dict can lead to crashes in threaded code. (Well, he says as long as you don't performing an assignment or a deletion in threaded code, there may be issues, but at least it shouldn't crash.) > For example if your proxy object has a __del__ method to clean up the > object it is proxying then you could be creating a new object with the same > oid as one that is in the process of being destroyed (the object disappears > from the WeakValueDictionary before the __del__ method is actually called). > > Without knowing anything about HDF5 I don't know if that's a problem but I > could imagine you could end up creating a new proxy object that references > something in the HDF5 library which you then destroy as part of cleaning up > a previous incarnation of the object but continue to access through the new > proxy. We started having problems when HDF5 began recycling oids as soon as their reference count went to zero, which was why we began using IDProxy and the registry. The IDProxy implementation below does have a __dealloc__ method, which we use to decrease the HDF5's internal reference count to the oid. Adding these proxies and registry dealt with the issue of creating a new proxy that references an old oid (even in non-threaded code), but it created a rare (though common enough) segfault in multithreaded code. This synchronized registry is the best I have been able to do, and it seems to address the problem. Could you suggest another approach? cdef IDProxy getproxy(hid_t oid): # Retrieve an IDProxy object appropriate for the given object identifier cdef IDProxy proxy proxy = registry.get(oid, None) if proxy is None: proxy = IDProxy(oid) registry[oid] = proxy return proxy cdef class IDProxy: property valid: def __get__(self): return H5Iget_type(self.id) > 0 def __cinit__(self, id): self.id = id self.locked = 0 def __dealloc__(self): if self.id > 0 and (not self.locked) and H5Iget_type(self.id) > 0 \ and H5Iget_type(self.id) != H5I_FILE: H5Idec_ref(self.id) -- http://mail.python.org/mailman/listinfo/python-list
Overriding a global
I've got a code pattern I use a lot. In each module, I create a logger
for the entire module and log to it all over:
logger = logging.getLogger('my.module.name')
class Foo:
def function(self):
logger.debug('stuff')
logger.debug('other stuff')
and so on. This works, but every once in a while I decide that a
particular function needs a more specific logger, so I can adjust the
logging level for that function independent of the rest of the module.
What I really want to do is:
def function(self):
logger = logger.getChild('function')
logger.debug('stuff')
logger.debug('other stuff')
which lets me not have to change any lines of code other than inserting
the one to redefine logger. Unfortunately, that's not legal Python (it
leads to "UnboundLocalError: local variable 'logger' referenced before
assignment").
Any ideas on the best way to implement this?
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Re: Overriding a global
On 10/12/2011 20:47, Roy Smith wrote:
I've got a code pattern I use a lot. In each module, I create a logger
for the entire module and log to it all over:
logger = logging.getLogger('my.module.name')
class Foo:
def function(self):
logger.debug('stuff')
logger.debug('other stuff')
and so on. This works, but every once in a while I decide that a
particular function needs a more specific logger, so I can adjust the
logging level for that function independent of the rest of the module.
What I really want to do is:
def function(self):
logger = logger.getChild('function')
logger.debug('stuff')
logger.debug('other stuff')
which lets me not have to change any lines of code other than inserting
the one to redefine logger. Unfortunately, that's not legal Python (it
leads to "UnboundLocalError: local variable 'logger' referenced before
assignment").
Any ideas on the best way to implement this?
You could use a different name:
def function(self):
logger2 = logger.getChild('function')
logger2.debug('stuff')
logger2.debug('other stuff')
or use 'globals':
def function(self):
logger = globals()['logger'].getChild('function')
logger.debug('stuff')
logger.debug('other stuff')
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Re: Overriding a global
MRAB wrote:
> or use 'globals':
>
> def function(self):
> logger = globals()['logger'].getChild('function')
> logger.debug('stuff')
> logger.debug('other stuff')
Ah-ha! That's precisely what I was looking for. Much appreciated.
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Re: Misleading error message of the day
On 12/09/2011 03:57 PM, alex23 wrote: On Dec 9, 11:46 am, Lie Ryan wrote: perhaps the one that talks about `a, a.foo = 1, 2` blowing up? Are you sure you're not confusing this with the recent thread on 'x = x.thing = 1'? Ah, yes I do -- http://mail.python.org/mailman/listinfo/python-list
Re: Multiprocessing bug, is information ever omitted from a traceback?
On 12/10/2011 2:02 PM, Chris Angelico wrote: There's a few differences between 2.6 and 2.7; not usually enough to be concerned about in daily use, but when dealing with weird issues, it helps to have the latest release. There are 2 issues. First, 2.7.2 has perhaps a couple hundred bug fixes since 2.7.0/2.6.6 were released. So it is possible that this particular problem was fixed, or at least changed. Second (leaving security issues aside), a Py2 bug fix will only be applied to the post-2.7.2 tip and only after the bug has been demonstrated to exist in the post-2.7.2 tip. About the request for minimal code exhibiting the problem: each bug exposes a hole in the test suite. We try to add a new test case with each bug fix so fixed bugs stay fixed. So code examples not only show that the bug is in the latest version, but also serve as the basis for new tests. -- Terry Jan Reedy -- http://mail.python.org/mailman/listinfo/python-list
Re: order independent hash?
On 12/09/2011 10:27 PM, Steven D'Aprano wrote: On Thu, 08 Dec 2011 10:30:01 +0100, Hrvoje Niksic wrote: In a language like Python, the difference between O(1) and O(log n) is not the primary reason why programmers use dict; they use it because it's built-in, efficient compared to alternatives, and convenient to use. If Python dict had been originally implemented as a tree, I'm sure it would be just as popular. Except for people who needed dicts with tens of millions of items. who should be using a proper DBMS in any case. -- http://mail.python.org/mailman/listinfo/python-list
Re: Overriding a global
On 12/10/2011 3:47 PM, Roy Smith wrote:
What I really want to do is:
def function(self):
Add a global statement to rebind a global name:
global logger
logger = logger.getChild('function')
logger.debug('stuff')
logger.debug('other stuff')
which lets me not have to change any lines of code other than inserting
the one to redefine logger. Unfortunately, that's not legal Python (it
leads to "UnboundLocalError: local variable 'logger' referenced before
assignment").
Any ideas on the best way to implement this?
--
Terry Jan Reedy
--
http://mail.python.org/mailman/listinfo/python-list
Re: order independent hash?
On Sun, Dec 11, 2011 at 10:58 AM, Lie Ryan wrote: > On 12/09/2011 10:27 PM, Steven D'Aprano wrote: >> Except for people who needed dicts with tens of millions of items. > > who should be using a proper DBMS in any case. Not necessarily. "Database" usually implies disk-based and relational, features that may well be quite superfluous; and a pure-memory database with no relational facilities... is basically a dict. So why not use one? ChrisA -- http://mail.python.org/mailman/listinfo/python-list
Re: Overriding a global
On 12/10/2011 7:14 PM, Terry Reedy wrote:
On 12/10/2011 3:47 PM, Roy Smith wrote:
What I really want to do is:
def function(self):
Add a global statement to rebind a global name:
global logger
But I see that that is not what you want to do, which is to override the
global name just within the function while still accessing the global
name. MRAB's solution does that nicely.
logger = logger.getChild('function')
logger.debug('stuff')
logger.debug('other stuff')
which lets me not have to change any lines of code other than inserting
the one to redefine logger. Unfortunately, that's not legal Python (it
leads to "UnboundLocalError: local variable 'logger' referenced before
assignment").
Any ideas on the best way to implement this?
--
Terry Jan Reedy
--
http://mail.python.org/mailman/listinfo/python-list
Re: order independent hash?
On 12/11/2011 11:17 AM, Chris Angelico wrote: On Sun, Dec 11, 2011 at 10:58 AM, Lie Ryan wrote: On 12/09/2011 10:27 PM, Steven D'Aprano wrote: Except for people who needed dicts with tens of millions of items. who should be using a proper DBMS in any case. Not necessarily. "Database" usually implies disk-based and relational, features that may well be quite superfluous; and a pure-memory database with no relational facilities... is basically a dict. So why not use one? It is very unlikely you'd have millions of items in a dict and you're not planning to do any data processing at all. In any case, there are very few use cases which requires the use of a dict with millions of items that wouldn't be better served by a proper database. -- http://mail.python.org/mailman/listinfo/python-list
Re: Dynamic variable creation from string
On Fri, 09 Dec 2011 01:55:28 -0800, Massi wrote: > Thank you all for your replies, first of all my Sum function was an > example simplifying what I have to do in my real funciton. In general > the D dictionary is complex, with a lot of keys, so I was searching > for a quick method to access all the variables in it without doing the > explicit creation: > > a, b, c = D['a'], D['b'], D['c'] > > and without using directly the D dictionary (boring...). If just you're trying to avoid getting a repetitive strain injury in your right-hand little finger from typing all the [''], you could turn the keys into object attributes, e.g.: class DictObject: def __init__(self, d): for key, value in d.iteritems(): setattr(self, key, value) ... o = DictObject(D) # use o.a, o.b, etc -- http://mail.python.org/mailman/listinfo/python-list
