Mailman 3 May 2001 - Python-list

Einstein's Riddle
by Steve Graham Sept. 17, 2015

Sept. 17, 2015

Who would be interested in using his/her brain (and his computer) to solve the following? Steve Graham === Einstein's Riddle Albert Einstein wrote this riddle this century [ed. 20th century]. He said 98% of the world could not solve it. There are 5 houses in 5 different colors. In each house lives a person with a different nationality. The 5 owners drink a certain type of beverage, smoke a certain brand of cigar, and keep a certain pet. No owners have the same pet, smoke the same brand of cigar or drink the same beverage. The question is: "Who owns the fish?" Hints: The Brit lives in the red house. The Sweed keeps dogs as pets. The Dane drinks tea. The green house is on the left of the white house. The green house's owner drinks coffee. The person who smokes Pall Mall rears birds. The owner of the yellow house smokes Dunhill. The man living in the center house drinks milk. The Norwegian lives in the first house. The man who smokes Blends lives next to the one who keeps cats. The man who keeps the horse lives next to the man who smokes Dunhill. The owner who smokes Bluemasters drinks beer. The German smokes Prince. The Norwegian lives next to the blue house. The man who smokes Blends has a neighbor who drinks water.

36 56

Python to C++ in a pickle
by Larry Whitley April 2, 2015

April 2, 2015

I'd like to pickle an object in python and unpickle it in C++. The object in question is a python dictionary so it will have to go into a C++ map. Has someone done this and is willing to share? Or, is the cPickle source available on the web somewhere? Larry

4 3

OPC for Python ?? (Win32)
by Armin Steinhoff March 24, 2014

March 24, 2014

Hi All, is there an implementation of OPC for Win32 Python available ?? ( http://www.opcfoundation.org ) Regards Armin

2 1

AIX installation can't find zlib
by Larry Whitley Nov. 3, 2011

Nov. 3, 2011

I've just installed the 1.5.2 source distribution on an AIX system and when I say "import zlib" it responds: >>> import zlib Traceback (innermost last): File "<stdin>", line 1, in ? ImportError: No module named zlib >>> I'm not sure where zlib is supposed to be. It's not in the Lib subdirectory of Python-1.5.2. In the Modules subdirectory I find zlibmodule.c. Nothing germaine in the Objects subdirectory. Looked at config.log and config.status, no mention of zlib. Looking at the sys.path I see: .../ldw/Python-1.5.2> python Python 1.5.2 (#1, Jul 26 2000, 14:21:56) [C] on aix4 Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam >>> import sys >>> sys.path ['', '/.../rchland.ibm.com/fs/u1/ldw/Projects/Programs/wtCache', '/.../rchland.ibm.com/fs/u1/ldw/Python-1.5.2/Lib/', '/.../rchland.ibm.com/fs/u1/ldw/Python-1.5.2/Lib/plat-aix4', '/.../rchland.ibm.com/fs/u1/ldw/Python-1.5.2/Lib/lib-tk', '/.../rchland.ibm.com/fs/u1/ldw/Python-1.5.2/Modules'] >>> Any suggestions? Larry

3 2

TopSort in Python?
by Tim Peters Jan. 21, 2008

Jan. 21, 2008

From: "Tim Peters" <tim_one(a)email.msn.com> [Dinu C. Gherman] > Does anybody have a simple-minded-but-working full-Python > implementation of topsort, the topological sorting algorithm? > Or maybe *any* topsort? I remember only one such algorithm... > python.org/search doesn't reveal any... Searching for "topological" instead turns up two hits there, a few more on DejaNews. Apparently "the std" algorithm I posted years ago predates DejaNews, though. So here's a fancier version ... check-out-aaron's-kjbuckets-too-ly y'rs - tim # topsort takes a list of pairs, where each pair (x, y) is taken to # mean that x <= y wrt some abstract partial ordering. The return # value is a list, representing a total ordering that respects all # the input constraints. # E.g., # topsort( [(1,2), (3,3)] ) # may return any of (but nothing other than) # [3, 1, 2] # [1, 3, 2] # [1, 2, 3] # because those are the permutations of the input elements that # respect the "1 precedes 2" and "3 precedes 3" input constraints. # Note that a constraint of the form (x, x) is really just a trick # to make sure x appears *somewhere* in the output list. # # If there's a cycle in the constraints, say # topsort( [(1,2), (2,1)] ) # then CycleError is raised, and the exception object supports # many methods to help analyze and break the cycles. This requires # a good deal more code than topsort itself! from exceptions import Exception class CycleError(Exception): def __init__(self, sofar, numpreds, succs): Exception.__init__(self, "cycle in constraints", sofar, numpreds, succs) self.preds = None # return as much of the total ordering as topsort was able to # find before it hit a cycle def get_partial(self): return self[1] # return remaining elt -> count of predecessors map def get_pred_counts(self): return self[2] # return remaining elt -> list of successors map def get_succs(self): return self[3] # return remaining elements (== those that don't appear in # get_partial()) def get_elements(self): return self.get_pred_counts().keys() # Return a list of pairs representing the full state of what's # remaining (if you pass this list back to topsort, it will raise # CycleError again, and if you invoke get_pairlist on *that* # exception object, the result will be isomorphic to *this* # invocation of get_pairlist). # The idea is that you can use pick_a_cycle to find a cycle, # through some means or another pick an (x,y) pair in the cycle # you no longer want to respect, then remove that pair from the # output of get_pairlist and try topsort again. def get_pairlist(self): succs = self.get_succs() answer = [] for x in self.get_elements(): if succs.has_key(x): for y in succs[x]: answer.append( (x, y) ) else: # make sure x appears in topsort's output! answer.append( (x, x) ) return answer # return remaining elt -> list of predecessors map def get_preds(self): if self.preds is not None: return self.preds self.preds = preds = {} remaining_elts = self.get_elements() for x in remaining_elts: preds[x] = [] succs = self.get_succs() for x in remaining_elts: if succs.has_key(x): for y in succs[x]: preds[y].append(x) if __debug__: for x in remaining_elts: assert len(preds[x]) > 0 return preds # return a cycle [x, ..., x] at random def pick_a_cycle(self): remaining_elts = self.get_elements() # We know that everything in remaining_elts has a predecessor, # but don't know that everything in it has a successor. So # crawling forward over succs may hit a dead end. Instead we # crawl backward over the preds until we hit a duplicate, then # reverse the path. preds = self.get_preds() from random import choice x = choice(remaining_elts) answer = [] index = {} in_answer = index.has_key while not in_answer(x): index[x] = len(answer) # index of x in answer answer.append(x) x = choice(preds[x]) answer.append(x) answer = answer[index[x]:] answer.reverse() return answer def topsort(pairlist): numpreds = {} # elt -> # of predecessors successors = {} # elt -> list of successors for first, second in pairlist: # make sure every elt is a key in numpreds if not numpreds.has_key(first): numpreds[first] = 0 if not numpreds.has_key(second): numpreds[second] = 0 # if they're the same, there's no real dependence if first == second: continue # since first < second, second gains a pred ... numpreds[second] = numpreds[second] + 1 # ... and first gains a succ if successors.has_key(first): successors[first].append(second) else: successors[first] = [second] # suck up everything without a predecessor answer = filter(lambda x, numpreds=numpreds: numpreds[x] == 0, numpreds.keys()) # for everything in answer, knock down the pred count on # its successors; note that answer grows *in* the loop for x in answer: assert numpreds[x] == 0 del numpreds[x] if successors.has_key(x): for y in successors[x]: numpreds[y] = numpreds[y] - 1 if numpreds[y] == 0: answer.append(y) # following "del" isn't needed; just makes # CycleError details easier to grasp del successors[x] if numpreds: # everything in numpreds has at least one predecessor -> # there's a cycle if __debug__: for x in numpreds.keys(): assert numpreds[x] > 0 raise CycleError(answer, numpreds, successors) return answer

8 9

Win32 drive mapping... aka "net use"
by lshuler＠my-deja.com March 5, 2005

March 5, 2005

Is there an API using Win32 extensions to map a drive share? I have not found one yet and have tried searching "Win32 map drive". I am looking for the equivalent of: net use <share path> If not, is there an alternative other than making a call to system("net use <path>"). Thanks in advance, Lance Sent via Deja.com http://www.deja.com/ Before you buy.

11 15

Blank ASP pages
by python Dec. 10, 2004

Dec. 10, 2004

My server is spitting out blank .asp pages which use python. If Python is not declared, the asp pages work fine. I just yesterday stepped up to Python 1.52 and the new win32all After the install, the blanks started appearing. All the paths look fine in registry. Any clues? ( Intel dual PIII 550 Xeon, 1G RAM, NT 4.0 SP 6a, IIS 4) ************************************************** Jason S. Nadler Lead Programmer Channel21 Productions, Inc. ... What are you doing right now? **************************************************

3 2

Dealing with faults matters (was: Is Python dying?)
by claird＠Starbase.NeoSoft.COM Aug. 28, 2003

Aug. 28, 2003

In article <3706f449.12085377(a)news.cybercity.dk>, Morten Christensen <mmc(a)vip.cybercity.dk> wrote: >On 31 Mar 1999 06:01:03 -0600, claird(a)Starbase.NeoSoft.COM (Cameron >Laird) wrote: >>*I* certainly discuss it. Anyone who understands >>that exception-handling is important I invite to >>realize that exception-handling on the sociologi- >>cal-organizational dimension has an even bigger >>multiplier. >> >>This is a plank of my "Visual C considered profes- >>sional malpractice" campaign. > >??? > >...I understand exception handling and regard it as very important, >although the (Visual) C++ implementation is really awful (as everyone >who have experienced "unexplainable" Visual C++ exceptions of unknown >origin and type knows ).... I also know a lot about how exception >handling is actually implemented in modern OO languages such as C++ >(this was the subject I wrote my master thesis on).... > >HOWEVER, I have NO clue about what you mean by exception-handling as a >multiplier on the sociological-organization dimension :-) I would like >to find out. Can you explain? . . . Happily. Excuse my giddiness, please; I see that that last message *did* wander too far into the land of obscurity. Here's what I was saying: exception-handling is important. Programs that intelligently use exception-handling mechanisms are better programs. Exception-handling is even more important to people. People and organizations that deal with exceptions intelligently, and don't pre- tend that everything should be without fault, are better people and organizations. In fact, a correct computer program often has over half its lines devoted to accomo- dating error. A wise person will have good ways to respond to criticism/problems/diffi- culties/...; dealing with success is relatively easier. -- Cameron Laird http://starbase.neosoft.com/~claird/home.html claird(a)NeoSoft.com +1 281 996 8546 FAX

3 2

Bug in v1.5.2 Websucker GUI?
by dhfx＠realtime.net June 13, 2003

June 13, 2003

I'm running v1.5.2 on a Win95 box. I tried wsgui.py and got the following error message: ... File "C:\ ... \WSGUI.PY", line 165, in go self.sucker.rootdir = os.path.dirname( [ websucker.Sucker.savefilename(self.url)) ] TypeError: unbound method must be called with class instance 1st arg (the part in [ ] didn't appear in the message - I added it from the code) The object-instance self.sucker is an instantiation of class SuckerThread, which is derived from class Sucker of the websucker code module. The SuckerThread class includes a method savefilename() which overwrites the method in websucker.Sucker of the same name. Whoever coded wsgui evidently wanted to use the method of the parent class, rather than the method of the derived class. What seems to be giving trouble is that the arg of dirname() is a class method, rather than a method of an instance of the class. Here's what I did: I defined a new method savefilename1() in SuckerThread which just calls the savefilename() of the parent class: def savefilename1(self, url): return websucker.Sucker.savefilename(self, url) Then I changed the code at "line 165" to the following: self.sucker.rootdir = os.path.dirname( self.sucker.savefilename1(url)) and now it works. Note that the arg "self" of savefilename1() in the line above is not needed, it's implicit. In fact, when I had it in, I got an error message that I had too many args! David Friedman

5 8

automating Outlook [repost]
by klassa＠ipass.net Aug. 30, 2002

Aug. 30, 2002

[ I managed to let this one slip by without a subject last time. Sorry for the repost. ] If you're interested in my motivation for this, see the footnote[1]. Bottom line: I wanted to be able to edit my drafts, in Microsoft Outlook, with the editor of my choice. In this case, Emacs. The following script does this for me... You tell Outlook to start a reply, and then you hit the "Edit" button that this script creates. It sucks the text out of Outlook, puts it into Emacs (you need to tweak the paths), then puts it back into Outlook when you're finished. The thing I'd like to add, still, is the ability to put an icon into the system tray, rather than have it be a free-floating application with a button. The sample code I found was a bit hard to grok (given that I'm not a Windows programmer, nor more than a novice python programmer). If you know how to do that, and would care to add it in, I'd love to hear from you. :-) The only snag I've found is that you can't run the script without having run makepy.py first, to make the Outlook library available. The full dynamic dispatch mechanism doesn't work, for some reason. That said, here's the script. It's undoubtedly ugly, but the important stuff is there. :-) -- snip -- import win32com.client import os import Tkinter from Tkconstants import * def launch(): # Default to an empty body. body = "" # Get a handle to Outlook. o = win32com.client.Dispatch("Outlook.Application") # Work our way down to the reply (a "MailItem"). insp = o.ActiveInspector() if insp == None: return item = insp.CurrentItem if item == None: return # Grab the body. body = item.Body # Should make this a guaranteed-unique file... fh = open("c:/temp/editor.txt", "w") # Write the body. Had to add a try/except because of ASCII # encoding problems when the reply is in one of Outlook's more # funky formats. try: fh.write(body) except: fh.write("") fh.close() # Launch emacs to edit the file. Should make this configurable. # Note that by default, Emacs seems to come up in Unix mode, and # so the ^M characters are visible. A persistent, bound-to-a-key # Emacs macro takes care of that nicely, however. os.spawnv(os.P_WAIT, "d:/Editors/emacs-20.7/bin/emacs", ["d:/Editors/emacs-20.7/bin/emacs", "c:/temp/editor.txt"]) # Read the result back into memory. fh = open("c:/temp/editor.txt", "r") body = fh.read() fh.close() # Store it as the body of the reply. item.Body = body # Create a single button that, when clicked, takes care of the rest. if __name__=='__main__': tk = Tkinter.Tk() frame = Tkinter.Frame(tk, relief=RIDGE, borderwidth=2, background="white ") frame.pack(fill=BOTH, expand=1) button = Tkinter.Button(frame, text="Edit", command=launch, background="white") button.pack(fill=BOTH, expand=1) tk.mainloop() -- snip -- Comments welcomed. John [1] Every so often, I make it a point to try some other language or tool, so as to widen my perspective a bit. For example, I'm an ardent emacs fan, but I've learned vi so that I'm able to edit anywhere (well, on any Unix machine), and so as to appreciate other ways to edit files. In this same way, I decided to try Microsoft Outlook. I'm an exmh hacker/fan (have been, for years), but thought I'd try Outlook just to see what my business/marketing/managements friends have to deal with. :-) My one biggest gripe is that you can't use the editor of your choice when you edit your drafts. The Outlook editor is okay... I mean, it's like every other Microsoft editor -- that is, reasonable, but lacking features (like the ability to reflow your text). So, I decided to give Outlook the ability to use the editor of my choice. I'm also a perl fan, but discovered that what I wanted to do was a lot harder (or at least seemed to be) in perl. So, I turned to python. Python seems to have a lot of nice Win32 support... This is maybe my fifth or sixth small python script, and I'm liking it (python) more and more.

3 3