🌐 Mailman 3 June 2006 - Python-list - python.org

what is the reasonable (best?) Exception handling strategy?
by Petr Jakes June 1, 2006

June 1, 2006

I am a little bit confused by all possibilities for exceptions handling in Python (probably because I am not skilled enough??) I did try to search trough this list and reading Python tutorial about Errors and Exceptions but didn't find some "general" answer about exception handling policy (strategy). In the following example each row can IMHO raise an exception (if the Firebird service is not running for example, if the database is corrupted etc.). Do I have to write "try/except" clause on each row? Or to write try/except block (function) where to handle (on one place) all exceptions expected in the program code is a good idea? Or do I have to write own "exception hook"? What about unexpected exceptions? :( def databasExample(h,d,u,p): import kinterbasdb; kinterbasdb.init(type_conv=200) con = kinterbasdb.connect(host=h, database=d,user=u, password=p) cur = con.cursor() insertStatement = cur.prep("some SQL statement......") cur.executemany(insertStatement, ListOfValues) con.commit() cur.close() Generally I am trying to find some general advices or suggestions about exception handling more than the specific answers to the above mentioned code example. Regards Petr Jakes

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Re: Tkinter - changing existing Dialog?
by John Machin June 1, 2006

June 1, 2006

Michael Yanowitz wrote: > Hello: > > > I have a Tkinter GUI Dialog with many buttons and labels and text > widgets. > So start a *new* thread.

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Re: Best Python Editor
by yairchu＠gmail.com June 1, 2006

June 1, 2006

> Can anyone tell me a good python editor/IDE? > It would be great if you can provide the download link also. WingIDE is very good. It gives very nice completions and has a nice thing called "source assistant" that shows the help of the function you're standing on and etc. But I don't think it's open-source and freei if that bothers you http://www.wingware.com/ Another good one is idlespoon. this one is open-source and freei http://idlespoon.python-hosting.com/

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Re: Function mistaken for a method
by Peter Otten June 1, 2006

June 1, 2006

Maric Michaud wrote: > Le Jeudi 01 Juin 2006 13:34, Peter Otten a écrit : >> A python-coded function has a __get__ attribute, a C-function doesn't. >> Therefore C1.f performs just the normal attribute lookup while C2.f also >> triggers the f.__get__(C2(), C2) call via the descriptor protocol which >> happens to return a bound method. > I don't think it's about c-coded versus python-coded stuff, C1.f is a > type, C2.f is a method. You are right, int is a type not a function, but presence (and implementation, of course) of __get__ is still the distinguishing factor: >>> class Int(int): ... class __metaclass__(type): ... def __get__(*args): print "XXX", args ... >>> class C: ... int = Int ... >>> C().int XXX (<class '__main__.Int'>, <__main__.C instance at 0x402948cc>, <class __main__.C at 0x40281f2c>) Also: >>> from math import sin >>> sin <built-in function sin> >>> def son(x): pass ... >>> class C: ... sin = sin ... son = son ... >>> C().sin(0) 0.0 >>> C().son(0) Traceback (most recent call last): File "<stdin>", line 1, in ? TypeError: son() takes exactly 1 argument (2 given) Peter

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How do you practice programming?
by Ray June 1, 2006

June 1, 2006

OK, maybe I shoot a more general question to the group since there are so many great programmers here: how do you practice your craft? I do it in the following way: 1. Set aside 30 minutes to 1 hour a day to read up on the latest development, be it about the tool I'm using, the language, or the platform, or the framework, etc. 2. Once every 1-2 months, go to Amazon, and look for the book with the best reviews in a particular technology (e.g.: SQL Cookbook, etc.) 3. Practice something that I may not be using currently at work, but always good to know, e.g.: I try to be reasonably competent in at least 2 major current languages--right now it's Java and C#, and 1 dynamic language, which has been Python for quite some time. SQL is always useful, so I try to practice that, especially the more complex queries involving group bys and window function, etc. How do you do your practice?

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Re: Watching serial port activity.
by Grant Edwards June 1, 2006

June 1, 2006

On 2006-05-31, Sergei Organov <osv(a)javad.com> wrote: > It seems that sniff on a real tty device could be implemented using the > same technique strace uses to intercept and show syscalls, though I'm > not aware of any sniffer application that does it. Using strace you can indeed trace read/write calls on user-specified file descriptors. Figuring out which file descriptors to trace is the tricky part. -- Grant Edwards grante Yow! I was making donuts at and now I'm on a bus! visi.com

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Re: Best Python Editor
by andyrsmith＠googlemail.com June 1, 2006

June 1, 2006

If we could go back to emacs again for a second... I'm still using emacs but have been playing with a few other ide's (wing, komodo + pydev) are the ones i've given a go recently. However I still end up coming back to emacs for what I consider to be emacs mode's piece of 'killer functionality', (well, killer for me anyway :-) ) which is the C-c C-c shortcut to send the contents of the current buffer to a running interpreter. (i.e. one long-running interpreter that behaves as if the entire buffer had been retyped). Not very useful on first glance, but compared with what I've found to be the 'standard' run-this-script-in-a-new-interpreter function the other ides seem to have it has the following advantages. 1/ No wait for another interpreter to start up 2/ It lets you do the following in a script which lends itself to a much tighter edit-run loop ... try: runOnce except: doSomePainfulDataGathering() runOnce = 1 doSomeLessPainfulDataProcessing() i.e. the painful part will only get executed once, so its cost can be amortized over multiple runs of the script. Of course care has to be taken to ensure the script doesn't violate causality (i.e. code can creep in that depends on variables that haven't yet been initialized) , but in practice I haven't found it to be much of a problem. (And can be checked quickly by simply killing the running interpreter and starting a fresh one). Anyway, the question is whether or not any of the other IDE's support this style of working, (I say I'd *played* with some of them but can't swear I'd dug through every nook and cranny of all of their menu options) Cheers, A.

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Re: Best Python Editor
by Rony Steelandt June 1, 2006

June 1, 2006

I have to admit that I'm testing eclipse with pydev at the moment, and it looks realy good Rony > Hi, > > Can anyone tell me a good python editor/IDE? > It would be great if you can provide the download link also. > > Thank You, > -Manoj- > > > "SASKEN RATED Among THE Top 3 BEST COMPANIES TO WORK FOR IN INDIA - SURVEY > 2005 conducted by the BUSINESS TODAY - Mercer - TNS India" > > SASKEN BUSINESS DISCLAIMER > This message may contain confidential, proprietary or legally Privileged > information. In case you are not the original intended Recipient of the > message, you must not, directly or indirectly, use, Disclose, distribute, > print, or copy any part of this message and you are requested to delete it > and inform the sender. Any views expressed in this message are those of the > individual sender unless otherwise stated. Nothing contained in this message > shall be construed as an offer or acceptance of any offer by Sasken > Communication Technologies Limited ("Sasken") unless sent with that express > intent and with due authority of Sasken. Sasken has taken enough precautions > to prevent the spread of viruses. However the company accepts no liability > for any damage caused by any virus transmitted by this email -- --- Rony Steelandt BuCodi rony dot steelandt (at) bucodi dot com Visit the python blog at http://360.yahoo.com/bucodi

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Re: Best way to do data source abstraction
by bruno at modulix June 1, 2006

June 1, 2006

Arthur Pemberton wrote: > What is the best way to do data source abtraction? For example have > different classes with the same interface, but different > implementations. > > I was thinking of almost having classA as my main class, and have > classA dynamically "absorb" classFood into to based on the extension > of the input file received by classA. But this doesn't seem possible. Could you explain more accurately what you're trying to do ? FWIW, it seems that a plain old factory function would do ? class DatasourceAbstraction(object): """ base class, factoring common stuff """ # implementation here class JpegFile(DatasourceAbstraction): # .... class PdfFile(DatasourceAbstraction): # .... class TxtFile(DatasourceAbstraction): # .... # etc _classes = { 'jpg' : JpegFile, 'txt' : TxtFile, 'pdf' : PdfFile, # etc.. } def Datasource(inputfile): ext = os.path.splitext(inputfile) return _classes.get(ext, <SomeDefaultClassHere>)(inputfile) The fact that there's no 'new' keyword in Python, and that classes are callable objects acting as factories means that it's a no-brainer to use a plain function (eventually disguised as a Class - the client code just doesn't care !-) as factory... Now if I missed the point, please give more explanations... -- bruno desthuilliers python -c "print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for p in 'onurb(a)xiludom.gro'.split('@')])"

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RE: Is device Connected Windows?
by Tim Golden June 1, 2006

June 1, 2006

[placid] | Just wondering is there a way (not brute force) to check if a usb | storage device is connected? Hmmm. How do you identify "a usb storage device" to know that it is or isn't connected? You can certainly do something useful with wmi. eg, <code> import wmi c = wmi.WMI () for usb_disk in c.Win32_DiskDrive (InterfaceType="USB"): print usb_disk.Caption print usb_disk.PNPDeviceID </code> Now, assuming that the PNPDeviceID is unique enough for your purpose, you could probably do something with it to keep hold of it and then check later whether the same device is still inserted. One possibility is to use a WMI watcher to spot when devices are removed: <code> import wmi c = wmi.WMI () usb_watcher = c.watch_for ( notification_type="Deletion", wmi_class="Win32_DiskDrive", delay_secs=2, InterfaceType="USB" ) while True: usb_removed = usb_watcher () # can optionally timeout print usb_removed.PNPDeviceID </code> Lots of other possibilities, a polling loop, two watchers, one for creation one for deletion etc. Depends exactly what your requirements are. TJG ________________________________________________________________________ This e-mail has been scanned for all viruses by Star. The service is powered by MessageLabs. For more information on a proactive anti-virus service working around the clock, around the globe, visit: http://www.star.net.uk ________________________________________________________________________

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