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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

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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

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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.

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Gate Oxide thickness of CMOS
by hasi＠rediffmail.com Jan. 2, 2005

Jan. 2, 2005

Hi, I would like to know the following details for a CMOS 1.gate oxide thickness 2.The Number of masks 3.Number of transistors per chip Thanks, Hasi!

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Parsing apache log files
by Fernando Rodr�guez Dec. 21, 2004

Dec. 21, 2004

Is there any module for parsing apache log files? O:-) I guess it could be done with regular expressions, but I'm not very gifted with them... :-) ----------------------- Fernando Rodriguez

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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? **************************************************

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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

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Bug? if PyGreSQL, inserttable is used followed by a for loop
by Anton Setzer June 16, 2003

June 16, 2003

Hi all, I had the following strange behaviour of python, which seems to be a bug, either in pygresql or in python itself. It happens when accessing postgresql through the module pg (PyGreSQL-3.2): After using inserttable, for-loops do no longer work. Here is an example session: I created a database marksadmin1 with no tables (adding a table kullm (e.g. CREATE TABLE kullm (stud text);) doesn't make any difference). Then when executing the following python program: import pg conn = pg.DB('marksadmin1') for j in []: print j conn.inserttable("kullm",[]) for j in []: print j conn.close() I get the following strange errormessage at the line with the second "for j in []"-loop (the first for-loop is okay): IndexError: list index out of range I am using python 2.2.1, PyGreSQL-3.2, postgresql version 7.2.1. The error seems to occur after any execution of inserttable (whether with an empty list or not) followed by arbitrary many commands followed by any "for j in mylist:"-loop. I have asked D'Arcy J.M. Cain, the current maintainer of PyGreSQL-3.2, who wasn't able to repeat that bug. However my installation seems to be the latest non-beta release and I haven't encountered any other bugs yet. Does anybody encounter the same problem? Or does anybody know what's wrong or what to do about it. Thanks for your time Anton Setzer -- ----------------------------------------------------------------------------- Anton Setzer Telephone: Department of Computer Science (national) (01792) 513368 University of Wales Swansea (international) +44 1792 513368 Singleton Park Fax: Swansea SA2 8PP (national) (01792) 295651 UK (international) +44 1792 295651 Visiting address: Email: a.g.setzer(a)swan.ac.uk Faraday Building, WWW: Computer Science Dept. http://www-compsci.swan.ac.uk/~csetzer/ 2nd floor, room 211. ------------------------------------------------------------------------------

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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

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FreeTDS vs Inline TDS: Problem with Inline TDS
by Sandeep Gupta April 5, 2003

April 5, 2003

I'm attempting to access a SQL Server 2000 DB from Linux using ODBC. My setup is Python --> mxODBC --> unixODBC --> <ODBC Driver> --> SQL Server When I use the Inline TDS driver directly from unixODBC, all queries return the correct results, but the final line is always "-1 rows affected". The FreeTDS driver returns the correct results as well as the correct number of rows affected. The incorrect "rows affected" from Inline TDS seems to be causing problems with mxODBC. Has anyone experienced this same problem with Inline TDS's driver? Are there any other suggestions for querying against SQL Server 2000 from Python running on Linux? Thanks Sandeep

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