How to create a PUG mailing list?
I'm trying to get a Python User Group started in Norman, OK and I want to get one of those fancy mailing lists on mail.python.org. There is a link there to create a new list if you have the proper authority. How does someone get the proper authority? -- Kevin D. Smith -- http://mail.python.org/mailman/listinfo/python-list
Debugging a Python Program that Hangs
I have a fairly large python program that, when a certain combination of options is used, hangs. I have no idea where it is hanging, so simply putting in print statements to locate the spot would be quite difficult. Unfortunately, ctrl-C'ing the program doesn't print a traceback either. Looking through the python debugger documentation, I don't see how to run a python program and interactively stopping it while it is running. Is there a way to stop within a running python program to see where it is getting hung up? -- Kevin D. Smith -- http://mail.python.org/mailman/listinfo/python-list
PIL: Getting a two color difference between images
I'm trying to get the difference of two images using PIL. The ImageChops.difference function does almost what I want, but it takes the absolute value of the pixel difference. What I want is a two color output image: black where the image wasn't different, and white where it was different. Right now I get black where it wasn't different, and abs(image1-image2) where it was different. It would be nice if I could specify the colors for difference and no difference. This sounds like it should be easy, but I just don't see how to do it. -- Kevin D. Smith -- http://mail.python.org/mailman/listinfo/python-list
Re: PIL: Getting a two color difference between images
On 2008-10-25 12:41:51 -0500, [EMAIL PROTECTED] said: Kevin D. Smith: What I want is a two color output image: black where the image wasn't different, and white where it was different.< There are several ways to do that. If speed isn't essential, then you can create a third blank image of the right size, and then use the method that iterates on the pixels of an image, and assign p1 != p2 at every pixel of the third image. If speed is important you can copy the images into numpy arrays and then your operation becomes easy. Maybe there are built-in ways in PIL too, I don't know. You can also find an intermediate solution, like computing the difference image with PIL and then binarize it manually. This last method is what I ended up doing for now. I use the PIL differencing function, then walk through the result of getdata() to binarize it. I was hoping there might be a way to run a filter or something that might be faster, but I haven't figured it out. -- Kevin D. Smith -- http://mail.python.org/mailman/listinfo/python-list
Doc strings in descriptors
I have a simple descriptor to create a cached property as shown below. class cproperty(object): """ Property whose value is only calculated once and cached """ def __init__(self, func): self._func = func self.__doc__ = func.__doc__ def __get__(self, obj, type=None): if obj is None: return self try: return getattr(obj, '@%s' % self._func.func_name) except AttributeError: result = self._func(obj) setattr(obj, '@%s' % self._func.func_name, result) return result The problem is that when I use the help() function on them, I don't get the doc string from the function that is being wrapped. Instead, I get the following: hasEmployees = What do I need to do to get the doc string of the wrapped function to apper when using help()? -- Kevin D. Smith -- http://mail.python.org/mailman/listinfo/python-list
heapq.merge with key=
I need the behavior of heapq.merge to merge a bunch of results from a database. I was doing this with sorted(itertools.chain(...), key=...), but I would prefer to do this with generators. My issue is that I need the key= argument to sort on the correct field in the database. heapq.merge doesn't have this argument and I don't understand the code enough to know if it's possible to add it. Is this enhancement possible without drastically changing the current code? -- Kevin D. Smith -- http://mail.python.org/mailman/listinfo/python-list
Re: heapq.merge with key=
On 2009-05-07 23:48:43 -0500, Chris Rebert said: On Thu, May 7, 2009 at 2:23 PM, Kevin D. Smith wrote: I need the behavior of heapq.merge to merge a bunch of results from a database. I was doing this with sorted(itertools.chain(...), key= ...), but I would prefer to do this with generators. My issue is that I need the key argument to sort on the correct field in the database. heapq.merge doesn't have this argument and I don't understand the code enough to know if it's possible to add it. Is this enhancement possible without drasticall y changing the current code? I think so. Completely untested code: def key(ob): #code here class Keyed(object): def __init__(self, obj): self.obj = obj def __cmp__(self, other): return cmp(key(self.obj), key(other.obj)) def keyify(gen): for item in gen: yield Keyed(item) def stripify(gen): for keyed in gen: yield keyed.obj merged = stripify(merge(keyify(A), keyify(B), keyify(C))) #A,B,C being the iterables Ah, that's not a bad idea. I think it could be simplified by letting Python do the comparison work as follows (also untested). def keyify(gen, key=lamda x:x): for item in gen: yield (key(item), item) def stripify(gen): for item in gen: yield item[1] After looking at the heapq.merge code, it seems like something like this could easily be added to that code. If the next() calls were wrapped with the tuple creating code above and the yield simply returned the item. It would, of course, have to assume that the iterables were sorted using the same key, but that's better than not having the key option at all. -- Kevin D. Smith -- http://mail.python.org/mailman/listinfo/python-list
Re: 2.6 windows install
On 2009-08-21 10:39:09 -0500, "Martin v. Löwis" said: Did you install Python to the network device from your XP box? That would explain why you can run it: the required registry settings & environment variables are added by the installer, none of which is occurring on any computer other than the one from which you installed. In principle, Python doesn't need any registry settings or environment variables in order to run. That may be true, but it doesn't explain why python won't run. I'm guessing that it has something to do with the msvc*90.dll files not getting installed. If those dlls haven't been previously installed, they won't be on the client machine in order for python to use them. However, I haven't had any luck installing these files manually and getting python to work that way. -- Kevin D. Smith -- http://mail.python.org/mailman/listinfo/python-list
Re: 2.6 windows install
On 2009-08-21 11:43:31 -0500, Kevin D. Smith said: On 2009-08-21 10:39:09 -0500, "Martin v. Löwis" said: Did you install Python to the network device from your XP box? That would explain why you can run it: the required registry settings & environment variables are added by the installer, none of which is occurring on any computer other than the one from which you installed. In principle, Python doesn't need any registry settings or environment variables in order to run. That may be true, but it doesn't explain why python won't run. I'm guessing that it has something to do with the msvc*90.dll files not getting installed. If those dlls haven't been previously installed, they won't be on the client machine in order for python to use them. However, I haven't had any luck installing these files manually and getting python to work that way. Installing those files from <http://www.microsoft.com/downloads/details.aspx?FamilyID=9b2da534-3e03-4391-8a4d-074b9f2bc1bf&displaylang=en> does seem to help, but python still gives an error of "The application failed to initialize properly (0xc00000022)." I'm not really sure where to go from here. -- Kevin D. Smith -- http://mail.python.org/mailman/listinfo/python-list
