🌐 Mailman 3 June 2007 - Python-list - python.org

socket.inet_ntop, and pton question
by Andrew Aug. 5, 2009

Aug. 5, 2009

Hi Are these functions (inet_ntop(), inet_pton()) from the socket library supported on Windows. If not is there an equivalent for them using Windows Ive seen mention of people creating their own in order to use them Appreciate the help ty

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Module for creating a screenshot of a web page given a URL?
by dananrg＠yahoo.com Oct. 23, 2008

Oct. 23, 2008

Is there a Python module that, given a URL, will grab a screenshot of the web page it goes to? I'd like to be able to feed such a module a list of URLs from a file. Thanks very much.

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Snapshot+Clipboard
by Yves Lange Oct. 23, 2008

Oct. 23, 2008

Hello, i'm searching a method to take a snapshot and save it in a jpg, bmp or gif file. I tried with win32api and win32con but it save the snapshot to the clipboard, so i tried to redirect this in a file but i have some problems while getting the IMAGE stocked in the clipboard and save it to a file. Can somebody help me ? Questions: -How can i read the snapshot in the clipboard ? -How can i take a snapshot in a different way (less difficult) ? Thks.

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Building a Python app with Mozilla
by Thorsten Kampe July 14, 2008

July 14, 2008

Hi, I've already sent this to the Komodo mailing list (which seemed to me the more appropriate place) but unfortunately I got no response. I'd like to build a Python GUI app. Neither Tkinter nor Wxpython nor PyQT are actually what I want (because the lack of GUI builders and they don't really look good on Windows and Linux). Komodo itself is an excellent example of a - at least Python driven - application that looks superb and has superior functionality so it seems natural to use the Komodo approach for me. Some questions * Is there a simple How-To how to build a very simple (Python) app with the Mozilla framework? Kind of "Hello world"...? * Is is reasonable to think that building a GUI with Mozilla is easier than using Python frameworks because Mozilla does most of the GUI work? Thorsten

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smtplib "authentication required" error
by carl.reimann＠gmail.com May 17, 2008

May 17, 2008

In using a simple smtp routine: # begin example >>> import smtplib >>> server = smtplib.SMTP('outgoing.verizon.net') >>> server.sendmail('my(a)address.net', 'another(a)address.net', """To: another(a)address.net From: my(a)address.net Subject: Shakespeare Quote Tis like the breath of an unfeed lawyer... """) >>> server.quit() # end example I find the following error: raise SMTPSenderRefused(code, resp, from_addr) smtplib.SMTPSenderRefused: (550, '5.7.1 Authentication Required', 'myuserid(a)verizon.net') I have attempted to incorporate into the interactive session: server.login = ('userid', 'password') # the same ones I use in my email program But I get the same error result. My objective is to have a simple way to send email from the command line. To do this I will write a script which can read in a file and send it to the address on top of the file. What is the procedure for authentication? Using the KMail email program (Linux, KDE desktop), I send mail through my Verizon account. Under the Configure KMail / Accounts / Modify Account / Extras tab, I clicked "Check what the server supports" and it came back 'no encryption' and 'cleartext'. So it doesn't seem that it would involve complex procedures. Any help welcome.

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Why can't timedeltas be divided?
by Dan Bishop April 27, 2008

April 27, 2008

If I try to write something like: num_weeks = time_diff / datetime.timedelta(days=7) I get: TypeError: unsupported operand type(s) for /: 'datetime.timedelta' and 'datetime.timedelta' Of course, one could extend the timedelta class to implement division, def _microseconds(self): return (self.days * 86400 + self.seconds) * 1000000 + self.microseconds def __truediv__(self, other): if isinstance(other, datetime.timedelta): return self._microseconds() / other._microseconds() else: return datetime.timedelta(0, 0, self._microseconds() / other) def __floordiv__(self, other): if isinstance(other, datetime.timedelta): return self._microseconds() // other._microseconds() return NotImplemented but why is a basic arithmetic operation missing from the standard datetime module?

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Python re expr from Perl to Python
by Michael M. Feb. 25, 2008

Feb. 25, 2008

In Perl, it was: ## Example: "Abc | def | ghi | jkl" ## -> "Abc ghi jkl" ## Take only the text betewwn the 2nd pipe (=cut the text in the 1st pipe). $na =~ s/\ \|(.*?)\ \|(.*?)\ \|/$2/g; ## -- remove [ and ] in text $na =~ s/\[//g; $na =~ s/\]//g; # print "DEB: \"$na\"\n"; # input string na="Abc | def | ghi | jkl [gugu]" # output na="Abc ghi jkl gugu" How is it done in Python?

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do design patterns still apply with Python?
by John Salerno Jan. 27, 2008

Jan. 27, 2008

Since Python does so many things different, especially compared to compiled and statically typed languages, do most of the basic design patterns still apply when writing Python code? If I were to read a design pattern book (such as Head First Design Patterns), could I apply their Java examples to Python easily enough, or does Python require a different perspective when applying patterns?

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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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subprocess "handle is invalid" error
by Grant Edwards Jan. 10, 2008

Jan. 10, 2008

I'm trying to use the py-gnuplot module on windows, and have been unable to get it to work reliably under Win2K and WinXP. By default, it uses popen(gnuplotcmd,'w'), but in some situations that consistently gets an "invalid operand" IOError when write() is called on the pipe. So I switched to subprocess. It works fine when executed "normally" (e.g. "python progname.py"), but when bundled by py2exe, it always does this: Traceback (most recent call last): File "surfedit.py", line 28, in ? File "Gnuplot\_Gnuplot.pyc", line 178, in __init__ File "Gnuplot\gp_win32.pyc", line 117, in __init__ File "subprocess.pyc", line 533, in __init__ File "subprocess.pyc", line 607, in _get_handles File "subprocess.pyc", line 634, in _make_inheritable WindowsError: [Errno 6] The handle is invalid How does one troubleshoot errors that happen three layers deep in the subprocess module? -- Grant Edwards grante Yow! I'm a fuschia bowling at ball somewhere in Brittany visi.com

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