🌐 Mailman 3 August 2004 - Python-list - python.org

Re: File System
by sjdevnull＠yahoo.com Aug. 31, 2004

Aug. 31, 2004

Aaron Bingham <bingham(a)cenix-bioscience.com> wrote in message news:<mailman.2656.1093944977.5135.python-list(a)python.org>... > Hello Maboroshi, > > You are not the first to think that there might be an alternative to the > filesystem. Here are a few links to sites for projects where > filesystems have been rethought or eliminated in very different ways. And let's not forget the reiserfs version 4 debate that's going on on the linux-kernel mailing list right now (and could potentially result in the fs being very different from the standard Unix fs, allowing a cyclic graph with object inheritance and complex query operations--or not, since it's not entirely clear that that's a good idea). Check out the thread "silent semantic changes with reiser4" and related threads at e.g. http://www.uwsg.iu.edu/hypermail/linux/kernel/0408.3/index.html I guess BeOS had a pretty unique FS as well, and its author (Dominic Giampalo) is working on a new FS for the Mac. And there's the (recently delayed) WinFS as well.

1 0

Re: GUI Wizard: flow control?
by djw Aug. 31, 2004

Aug. 31, 2004

David Chan wrote: > Hi, > > I'm trying to use python to create GUI wizards, i.e. sequences of dialog > boxes with <BACK and NEXT> buttons. Since I want to re-use some of the > dialog boxes in different wizards, I want to have a main function which > calls each dialog box, much like this: > > def select_item(): > """runs GUI wizard to select item""" > > client = show_client_dialog() > job = show_job_dialog(client) > invoice, rate = show_invoice_dialog(job) > item = choose_item_dialog(invoice, rate) > return item > > This works fine until you want to implement the <BACK button, which should > return to the previous dialog. Theoretically, what I'd really like is to > be able to jump backwards through the control flow, like this: > > class GoBack(Exception): pass > def select_item(): > """runs GUI wizard to select item - can go <BACK""" > back = HERE > client = show_client_dialog() > > try: job = show_job_dialog(client) > except GoBack: back.goto() > back = HERE > > try: invoice, rate = show_invoice_dialog(job) > except GoBack: back.goto() > back = HERE > > try: item = show_item_dialog(invoice, rate) > except GoBack: back.goto() > > return item > > But I couldn't find a way of doing anything like that. You could do > something almost as unhorrible with nested breaks:' > > class GoBack(Exception): pass > def select_item(): > """runs GUI wizard to select item - can go <BACK""" > CLIENT: while 1: > client = show_client_dialog() > > JOB: while 1: > try: job = show_job_dialog(client) > except GoBack: continue CLIENT > > INVOICE: while 1: > try: invoice, rate = show_invoice_dialog(job) > except GoBack: continue JOB > > try: item = show_item_dialog(invoice, rate) > except GoBack: continue INVOICE > break CLIENT > > Or you could do all the flow control manually in a "do_wizard" function > and make the caller create a horrible data structure instead of writing > readable code: > > calls = [ > {'meth': show_client_dialog, 'args': [], 'ret': ['client']}, > {'meth': show_job_dialog, 'args': ['client'], 'ret': ['job']}, > {'meth': show_invoice_dialog, 'args': ['job'], 'ret': ['invoice', > {'rate']}, 'meth': show_item_dialog, 'args': ['invoice', 'rate'], > {'ret': ['item']}, > ] # this just says: "client = show_client_dialog()", etc. > do_wizard(calls, locals()) > > > But this is too hideous to deploy, because I might have to remember what > it does in six months :-) > > Can anyone suggest something better, or should I abandon my goal of having > a main function which calls each dialog box? > > Many thanks, I always code this sort of situation up as a simple state machine. Each NEXT/BACK button controls the next state, each state being the display of a particular dialog. A state machine can be a good candidate for flow control that has to go "forwards" and "backwards". -Don

1 0

MSI Installer Problem: can't install 2.4a2 on new install of Win2kSP2
by Richard Hanson Aug. 31, 2004

Aug. 31, 2004

Over the last few days, I reinstalled Win2kSP2 to a spare harddrive I had just swapped into my Fujitsu LifeBook P1120 (long story <wink>). Subsequently, I DL'ed the newest Python alpha (2.4a2), and when trying to install it, I immediately got this error: This installation package cannot be installed by the Windows Installer service. You must install a Windows service pack that contains a newer version of the Windows Installer service. (Python 2.4a2 had been working on the LifeBook P1120 before the crash and subsequent reinstall.) I immediately tried installing Python 2.4a2 on my older, HP laptop, and that went fine. I then went back to the Python alpha page and DL'ed the ~1.8MB file linked from MS's site. After running the new DL from MS, the Python MSI installer seemed to run. However, now Idle wouldn't run, although the Python command line (console) worked. I tried running Idle using Windows Explorer from inside my Python installation at: E:\Python24\Lib\idlelib\idle.pyw (and idle.py) but those didn't work, either. (E:\ is my Win2k partition and it's a FAT32 partition.) I then checked the new 2.4a2 install on the older HP laptop, and there Idle worked -- from the menu shortcuts, and from launching the idle.pyw file in Windows Explorer. (I note that the HP laptop already had Python23 on it. The HP has *almost* the same OS: Win2kSP3 -- not a fresh install -- and is using NTFS for its Win2k partition.) I also note that the *.pyc files were not created by the installer on the Fujitsu LifeBook P1120 but were on the HP Omnibook 900B (as may be surmised). Back on the P1120, I used the MSI installer to "repair" the broken install twice, used it again to completely remove Python, rebooted <wink>, and then use the MSI installer one more time to reinstall. Still no go. Am I overlooking something simple...? Thanks for any help anyone can offer. (I'll try to followup as this gets solved -- I've reinstalled onto an old harddrive, so I may crash again... :-) ) I'll-keep-at-it-and-try-DL'ing-2.3.4-tonight'ly y'rs Richard -- email works if unmunged: sick<PERI0D>ole<P0INT>fart<PIE_DEC0_SYNTAX>newsguy<MARK>com

4 12

Re: mySQL access
by deelan Aug. 31, 2004

Aug. 31, 2004

Greg Lindstrom wrote: > Hello- > > I'd like to connect to a mySQL database from Python 2.3 on Windows XP. I've > read up on the mySQLdb module, but do not have Microsoft Visual Studio for > the C++ compile part of the exercise. Am I hosed? Or is there a way do > this without having to have VS? maybe i'm missing something, but there is a win32 binary download for mysqldb 1.0 on sf.net: <http://prdownloads.sourceforge.net/mysql-python/MySQL-python-1.0.0.win32-py…> project page: <http://sourceforge.net/projects/mysql-python/> HTH, deelan -- @prefix foaf: <http://xmlns.com/foaf/0.1/> . <#me> a foaf:Person ; foaf:nick "deelan" ; foaf:weblog <http://www.netspyke.com/> .

2 1

RE: GUI Designer
by Batista, Facundo Aug. 31, 2004

Aug. 31, 2004

[A.M] #- Do we have any OpenSource GUI designer for Python ? That depends heavily on what GUI you're developing. Have you chosen one? . Facundo

1 0

mySQL access
by Greg Lindstrom Aug. 31, 2004

Aug. 31, 2004

Hello- I'd like to connect to a mySQL database from Python 2.3 on Windows XP. I've read up on the mySQLdb module, but do not have Microsoft Visual Studio for the C++ compile part of the exercise. Am I hosed? Or is there a way do this without having to have VS? Thanks, --greg Greg Lindstrom (501) 975-4859 NovaSys Health greg.lindstrom(a)novasyshealth.com "We are the music makers, and we are the dreamers of dreams" W.W.

1 0

Re: has_method (solution found)
by Eric Brunel Aug. 31, 2004

Aug. 31, 2004

Gandalf wrote: > > Somebody sent me a private e-mail. > It must be common for such silly questions that would just spam the > list. :-) > I'll write down the final solution anyway. > > > def getmethod(name): > methodList = [e for e in dir(self) if callable(getattr(self, e))] > if name in methodList: > return getattr(self,name) > else: > return None And why not: def getmethod(obj, name): meth = getattr(obj, name) if callable(meth): return meth else: return None ??? Why do you use a list comprehension to get the names of all methods on the object? In addition, it won't work for class instances: >>> class C: ... def m(self): ... print 'spam' ... >>> >>> o = C() >>> dir(o) [] But: >>> getattr(o, 'm') <method C.m of C instance at 0x821433c> HTH -- - Eric Brunel <eric (underscore) brunel (at) despammed (dot) com> - PragmaDev : Real Time Software Development Tools - http://www.pragmadev.com

2 1

Re: Splitting a list
by Peter Otten Aug. 31, 2004

Aug. 31, 2004

Jeff Epler wrote: > Here's my version as a generator function: > def split(it, elem): > l = [] > for i in it: > if i == elem: > yield l > l = [] > else: > l.append(i) > yield l > A clean algorithm, but it has one corner case that strikes me as counterintuitive: >>> list(split([], None)) [[]] I would prefer [], so I cross-checked with str.split(): >>> "".split() [] >>> "".split("x") [''] Strange. Is that by design or by accident? Peter

1 1

Re: Splitting a list
by Paul McGuire Aug. 31, 2004

Aug. 31, 2004

"Ian Sparks" <Ian.Sparks(a)etrials.com> wrote in message news:mailman.2673.1093960462.5135.python-list@python.org... string.split() is very useful, but what if I want to split a list of integers on some element value? e.g. : >> l = [1,2,3,-1,4,5,-1,8,9] >> l.split(-1) >> [[1,2,3],[4,5],[8,9]] Here's my hideous first pass : >> [[int(z) for z in x.split(',') if z] for x in ','.join([str(a) for a in l]).split('-1')] >> [[1, 2, 3], [4, 5], [8, 9]] When I see code like that I just know I've missed something obvious.... Maybe not the prettiest, but here's a solution using a generator (at least you're avoiding a bunch of conversions to/from string). -- Paul l = [1,2,3,-1,4,5,-1,8,9] def getSublists(lst, delim): loc = 0 while loc < len(lst): try: nextloc = lst.index(delim,loc) except ValueError: nextloc = len(lst) yield lst[loc:nextloc] loc = nextloc+1 print [ sub for sub in getSublists(l,-1) ]

1 0

Changing the decimal separator to a comma
by andrew.jewell＠upm-kymmene.com Aug. 31, 2004

Aug. 31, 2004

I've tried using the locale module to set the locale correctly, but all I get is "Error: unsupported locale setting". I'm not actually sure what the proper setting should be; I think it's "fi" for Finland, but this is what I get when I try (under py 2.2): >>> locale.setlocale(locale.LC_ALL,"fi") Traceback (most recent call last): File "<stdin>", line 1, in ? File "/usr/python2.2.2/lib/locale.py", line 372, in setlocale return _setlocale(category, locale) locale.Error: locale setting not supported Under 2.3 the call succeeds but makes no difference to the decimal point (which should be a comma for Finland): >>> locale.setlocale(locale.LC_ALL,"fi") 'Finnish_Finland.1252' >>> 0.123 0.123 >>> "%10.2f" % 0.123 ' 0.12' The program I'm working on produces database records using a format string, and I'm currently manually tracking all the dp's and replacing them in a loop, just before writing the record to disk, but this is inefficient and inelegant. What I'd *like* to be able to do is specify that we want to use commas for dp's or adjust the locale settings accordingly, then just write the records directly from the format string... regards, -andyj

2 1