Deterministic destruction and RAII idioms in Python

I have been dabbling in Python for a while now. One of the things that really appeals to me is that I can seem to be able to use C++-style RAII idioms to deal with resource management issues. For those that have no idea what I am talking about (I learn a lot reading posts on subjects in which I a

Re: Deterministic destruction and RAII idioms in Python

Thanks to all who replied. This has definitely given me something to chew on. I looked at pep-0343, it looks interesting. It is not what I really want (deterministic destruction) but it is a lot more than most GC'ed languages give me (Java, I am looking at you... :-) ). As far as my comment abo

Re: Deterministic destruction and RAII idioms in Python

Hi Paul, >> I looked at pep-0343, it looks interesting. It is not what I really >> want (deterministic destruction) > >I think it's better. Is there something specific you have in mind that makes you say that? I am not a python expert, so I probably do not understand all the implications of the

Re: Deterministic destruction and RAII idioms in Python

Hi Paul, > I didn't understand then. I thought by "deterministic destruction" > you meant relying on what CPython does now, which is reference > counting with destruction when the last reference is released. I effectively do mean that. In C++ it is guaranteed that a destructor will be called

Re: 450 Pound Library Program

Ok, I give up. DRY = Don't Repeat Yourself (google Pragmatic Programmers) but SPOT? Google is little help here, SPOT is too common a word. Thanks! -- http://mail.python.org/mailman/listinfo/python-list

Re: arrays in python

> Oh, don't tell me, I love playing guessing games! Don't you mean "No no... don't tell me. I'm keen to guess." Sorry, I couldn't resist... :-) (for those who just went huh?, see http://www.aldo.com/sgt/CheeseShoppeSkit.htm) -- http://mail.python.org/mailman/listinfo/python-list

Re: RSA in python

stupid question, but did you try: rsa = M2Crypto.RSA.load_pub_key( file("pubkey.pem") ) It is not clear from the documentation what they want for "file" (and because Python has no type declarations, you are left to guess...). May not work... just thought I would ask. -- http://mail.python.org/

Re: RSA in python

Looking at the api documentation again, it is possible that they want this: pubkey = open( 'pubkey.pem', 'rb' ).read() # binary read here? rsa = M2Crypto.RSA.load_pub_key(pubkey) Anyway, things to play with... -- http://mail.python.org/mailman/listinfo/python-list

Re: general coding issues - coding style...

Hi, 1585 if sys.path[0][-12:] == "\library.zip": #for py2exe how about if sys.path[0].endswith( "\\library.zip" ): (did you really mean one back-slash there?) 499 tuple = os.path.split(filename) bad variable name... tuple(x) converts a sequence to a tuple. You have a number of places

Re: Regular expression gone mad

This may not be enough for what you really want to do, but, given what you have shown above, regex is the wrong tool for the job. Use the string method startswith: for line in ProcMem.split('\n'): if line.startswith( 'Mem' ): # do stuff -- http://mail.python.org/mailman/listinfo/pyt

Re: Processing text using python

Hi, you have plenty of good responses. I thought I would add one more: def data_iter(file_name): data = file(file_name) while True: value = data.read(3) if not value: break yield value data.close() With the above, you can grab the entire data set

Re: What's up with this code?

Scott, this was a really clever catch, but I don't agree with the solution. The problem is your assumption of how zip/izip _must_ work. I don't think there is any contract that states that they will always advance the first argument first and the second argument second... that is an implementatio

Re: problem(s) with import from parent dir: "from ../brave.py import sir_robin"

You don't _need_ to go the PYTHONPATH route (although that works). Re-read Carsten's post (particularly step 1, see section 6.1.1). You can use: sys.path.append('..') from brave import sir_robin -- http://mail.python.org/mailman/listinfo/python-list

Re: Regular expression fun. Repeated matching of a group Q

Doesn't this do what you want? import re DATE_TIME_RE = re.compile(r'((\d{2}\/\d{2}\/\d{4})|(\d{2}:\d{2}))<\/td>') test = '04/01/2006' \ 'Wednesday' \ ' ' \ '09:14' \ '12:44' \ '12:50' \ '17:58' \ ' ' \ ' '

raw strings and \

I thought I understood raw strings, then I got bitten by this: x=r'c:\blah\' which is illegal! I thought that \ had no special meanning in a raw string so why can't it be the last character? making me do: x=r'c:\blah' '\\' is just silly... -- http://mail.python.org/mailman/listinfo/python-l

Re: raw strings and \

Hi Duncan, thanks for the reply. I figured that this was a technical problem associated with the parser. This one is going on my Python gotchas list. It is really silly from an end user perspective to have \ not special in raw strings _except_ if it is the last character. -- http://mail.pytho

Re: How to except the unexpected?

>Yes, and that's the Right Thing(tm) to do. Source code don't lie. Source > code don't get out of sync. So source code *is* the best documentation >(or at least the most accurate). I could not disagree more strongly with this. Not just no, but hell no! >Yes, and that's the Right Thing(tm) to do

Re: raw strings and \

Hi, thanks for the reply. I was not aware of this in raw strings (and frankly, don't like it... but who cares about that :-) ) When I needed embedded quotes in a raw string I went the triple quote route: a = r'''check \' this''' which makes more sense to me. -- http://mail.python.org/mailman

Re: raw strings and \

Hi Alex, thanks for the reply. I can see that there is a choice that needed to be made. Before I was aware of the \ issue I just used (yes it has come up, but the example is at work) triple quotes to work around the embedded quote issue: x=r'''It's like this "c:\blah\" ok?''' print x It's like

Re: raw strings and \

Hi Steven, thanks for the reply. I was/am aware that raw strings are mainly used for regular expressions (and franky that was I usually use them for). I was not aware that they still have "special powers" in raw strings (thanks for the link!). This one bit me when I was doing some quick and dirt

Re: raw strings and \

>Alas, somebody will now quote Emerson at you, I fear;-). Let them come :-) I almost always see this (mis)quoted as: "consistency is the hobgoblin of little minds" which is not really what Emerson said. The full quote is: "A foolish consistency is the hobgoblin of little minds" I would say t

Re: raw strings and \

Interesting, so thats where this comes from. Of course the problem is that I thought that a raw string was a different animal than a regular string (i.e. truely "raw" where no characters are special, except of course the closing quote) so parsing consistency is surprising to an end user (who has a

Re: API/C memory mananegemnt problem

I have not looked into C programming and Python so I probably don't understand the issues here but the above statement sounds very troubling. Does this mean that any integer or float created anywhere at anytime in a (pure) python program will be stored away for all time (as long as the program is

Re: API/C memory mananegemnt problem

Sorry for responding to my own post. I think I understand the original statement now. What you are really saying is that there is a pool of Python float objects (which can, at different times, wrap different values) which can grow but never decrease in size. So the memory held by this pool is di

Re: API/C memory mananegemnt problem

This exactly what I was thinking. Are we wrong Alex? -- http://mail.python.org/mailman/listinfo/python-list

Re: How to check if a directory is exist in python?

Check out os.path.isdir(path_name) http://docs.python.org/lib/module-os.path.html -- http://mail.python.org/mailman/listinfo/python-list