This may seem simple and trivial, but today I discovered the basestring type in Python. It is essentially a base type for str and unicode, which comes in handy when writing isinstance(foo, basestring) in test code for example.
Strangely, despide PEP 237 mentioning the equivalent for int and long …
When you have someplace where you register a set of callbacks you have a few options:
Pointer arithmetic in C is great. The only downside is that it's only defined when pointing to an array (or an item just after the array). That is one giant downside.
Allocate a chunk of memory and you can't use pointer arithmetic. So if you are building a linked list …
Catherine Devlin describes it very nicely:
I finally understand Al-Qaeda's master plan, and it's freaking brilliant. [...] I'm just surprised that we're choosing to participate in the plan. I thought we were on opposite sides?
Why was it ever considered desirable to call a directory containing a __init__.py file a "package" rather then just "module". They are after all simply "modules containing other modules". It's not like that solved some sort of problem was it? But, as sad as that sometimes might be, we …
Most important thing first: the eLOM console lives on ttyS1 (9600n8). If that gets you going you do not need to read any more.
This works pretty easily, but there's isn't much information about how this works if you don't like using a keyboard and a screen (having these things …
My gut tells me it's horribly wrong but I am failing to formulate a decent argument, let me show an example what I mean (somewhat contrived):
def deco(f):
def wrapper(self, *args, **kw):
with self.lock:
f(self, *args, **kw)
class Foo:
def __init__(self):
self.lock = threading.Lock …This counts for one of the more crazy things I'd like to do with Python: insert an instance of a descriptor object into the class dict of a module.
While you can get hold of the module type class by using the __class__ attribute of any module or use types …
If you got a test suite that runs some very slow tests it might be troublesome to run those all the time. There is of course the "-k" option to py.test which allows you to selectively enable only a few tests. But what I really wanted was a way …
In case you heard of both setuptools and distribute: distribute fully replaces setuptools. Just use distribute. Setuptools is “maintained” (for various historically dubious values of “maintain”) by one person (whom all should applaud for creating the darn thing in the first place, btw!). Distribute is maintained by …
innovative company
noun 1 a company which can't afford patent lawyers *2 one of the lucky handful companies who are innovative and have money for patent lawyers *HELP Not to be confused with most companies lobying in patent litigation.
PS: It's also possible to have companies that can't afford patent …
If you are driving on a motorway where I am driving too, here are some rules you should follow. I think you should even follow them when I'm not around.
When connecting two computes together (e.g. your laptop to a server or router) to get access to a console you need to use a crosslinked RS-232 cable, usually with two female DE-9 connectors these days. This cable is more commonly known as a …
Do not, I repeat, do not define .__getstate__() idly.
Thank you very much
Todays pleasant surprise:
>>> a = {'a': (0, 1), 'b': (2, 3)}
>>> for k, (v1, v2) in a.iteritems():
... print k, v1, v2
...
a 0 1
b 2 3
>>>
Nice!
I can't help but agree.
After reading Ned Batchelder's post on his experience hunting a memory leak (which turned out to be a reference counting error) it occurred to me that even tough I have a script to check memory usage I should also really be checking reference counts with sys.gettotalrefcount(). And indeed, after …
I've just released a new version of PSI! PSI is a cross-platform Python package providing real-time access to processes and other miscellaneous system information such as architecture, boottime and filesystems. Among the highlights of this release are:
What I'd like to build is an object that when doing anything with it would first acquire a lock and release it when finished. It's a pattern I use fairly-regularly and I am getting bored of always manually defining a lock next to the other object and manually acquiring and …
I've never understood if you can use GPL python modules (or packages) in GPL-incompatibly licensed code. Today I re-read the GPL looking for this and am tempted to think yes, you can. The GPL says:
- You may copy and distribute verbatim copies of the Program's source code as you receive …
A little while ago I released a new version of Delny (my python wrapper around Qhull for Delaunay triangulations), the main purpose to use numpy instead of numeric. Impressively enough people actually seemed to care and I got a few bug reports and hints for improvements.
So I just released …
So I'm looking at the release notes for Ubuntu 9.10 and am interested in the hibernation issue. Naturally I follow the link to the bug report.
First I need to log in to launchpad. That's weird, since when do I need to log in simply to view bugs? But …
At work we have an rather elaborate collection of shell scripts that builds our softweare and all it's dependencies on about 7 UNIX variants as well as on Windows. Shell seemed like a good choice when we started to write those scripts: it is available on all hosts (using Cygwin …
Normally I'm quite happy with the 3h of battery life of my laptop, it covers all my disconnected time on trains etc. But it just doesn't cut it on a 10h flight, especially painful if my brain has loads of ideas to try out and things to do.
Sometimes you have to transfer data over dodgy links. And when you're transferring a large file this can hurt when it fails. So as explained elsewhere rsync can safe the day:
$ scp host:remote_file local_file
# now interrupt and resume with
$ rsync --partial --progress --rsh=ssh host:remote_file local_file
You need …
Firstly to clarify the terminology, this is bare except statement:
try:
...
except:
...
And this is a non-bare except statement, but bear in mind the type of the exception that is caught can be anything:
try:
...
except Exception:
...
The point is that both fragments are a catch-all exception handler, only the …
I've spent the last 2 days trying to get a stack trace from a crashing python extension module in windows. And I still haven't figured it out. That's sooo very motivating.
Give me GNU/Linux any day.
Often it's nice to just have conventions and gentleman's agreements. But then sometimes someone doesn't and the harm is done, it's too hard to reverse.
NFS has introduced the de-facto standard of using <host>:<path> for the device of a remote mount. Yes this break because you can have ":" in …