Re: Don't use __slots__! (was Re: dicts vs classes)
In article <[EMAIL PROTECTED]>, Roy Smith <[EMAIL PROTECTED]> wrote: >>Guido sez: >> >> __slots__ is a terrible hack with nasty, hard-to-fathom side >> effects that should only be used by programmers at grandmaster and >> wizard levels. Unfortunately it has gained an enormous undeserved >> popularity amongst the novices and apprentices, who should know >> better than to use this magic incantation casually. > >But, if they are novices, why should they be expected to know better? > >I just re-read http://docs.python.org/ref/slots.html#l2h-217 and don't >see anyplace where it says, "Warning: for use by wizards only". Unfortunately, the Python docs are currently suboptimal when it comes to new-style classes. -- Aahz ([EMAIL PROTECTED]) <*> http://www.pythoncraft.com/ "Debugging is twice as hard as writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it." --Brian W. Kernighan -- http://mail.python.org/mailman/listinfo/python-list
Re: dicts vs classes
Don't optimize prematurely. Write whatever is cleaner, simpler and makes more sense. Such that if someone (or even yourself) looks at it 10 years from now they'll know exactly what is going on. As far as what is slower or what functionality you will use and what you won't -- well, if you won't use it then why worry about it and to find out if it is slower run a quick benchmark and you'll know... -NickV [EMAIL PROTECTED] wrote: > Simon Hibbs: > > It seems to me that unless you > > need some of the functionality supplied with dictionaries (len(a), > > has_key, etc) then simple objects are a syntacticaly cleaner and more > > natural way to express yourself. > > I'd say the opposite. Classes contain a dict of their attributes, etc. > So if you don't need the functionality supplied by objects, then using > simpler dictionaries is better. (But in the end the choice has to be > made according to the specific situations). > > Bye, > bearophile -- http://mail.python.org/mailman/listinfo/python-list
Re: Don't use __slots__! (was Re: dicts vs classes)
>Guido sez: > > __slots__ is a terrible hack with nasty, hard-to-fathom side > effects that should only be used by programmers at grandmaster and > wizard levels. Unfortunately it has gained an enormous undeserved > popularity amongst the novices and apprentices, who should know > better than to use this magic incantation casually. But, if they are novices, why should they be expected to know better? I just re-read http://docs.python.org/ref/slots.html#l2h-217 and don't see anyplace where it says, "Warning: for use by wizards only". -- http://mail.python.org/mailman/listinfo/python-list
Re: Don't use __slots__! (was Re: dicts vs classes)
In article <[EMAIL PROTECTED]>, <[EMAIL PROTECTED]> wrote: >Aahz, citing Guido: >> >>__slots__ is a terrible hack with nasty, hard-to-fathom side >>effects that should only be used by programmers at grandmaster and >>wizard levels. Unfortunately it has gained an enormous undeserved > >I think I have used __slots__ just one time. Can you tell me some of of >such bad side effects? The main one is that inheritance becomes difficult to nearly-impossible. -- Aahz ([EMAIL PROTECTED]) <*> http://www.pythoncraft.com/ "Debugging is twice as hard as writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it." --Brian W. Kernighan -- http://mail.python.org/mailman/listinfo/python-list
Re: dicts vs classes
Simon Hibbs wrote: > I'm wondering about whether to use objects in this way or dictionaries > for a program I'm writing at the moment. It seems to me that unless you > need some of the functionality supplied with dictionaries (len(a), > has_key, etc) then simple objects are a syntacticaly cleaner and more > natural way to express yourself. > > Any objctions to this, or pitfalls? > > Simon Hibbs I'm not sure, but I think this should be the other way round: unless you need special behavior that dicts don't supply (methods) or you really want/need obj.attr notation, you're better off just using dicts, but Marco Wahl is right, if it really matters measure it. Peace, ~Simon -- http://mail.python.org/mailman/listinfo/python-list
Re: Don't use __slots__! (was Re: dicts vs classes)
Aahz, citing Guido: >__slots__ is a terrible hack with nasty, hard-to-fathom side >effects that should only be used by programmers at grandmaster and >wizard levels. Unfortunately it has gained an enormous undeserved I think I have used __slots__ just one time. Can you tell me some of of such bad side effects? Bye, bearophile -- http://mail.python.org/mailman/listinfo/python-list
Re: dicts vs classes
Simon Hibbs: > It seems to me that unless you > need some of the functionality supplied with dictionaries (len(a), > has_key, etc) then simple objects are a syntacticaly cleaner and more > natural way to express yourself. I'd say the opposite. Classes contain a dict of their attributes, etc. So if you don't need the functionality supplied by objects, then using simpler dictionaries is better. (But in the end the choice has to be made according to the specific situations). Bye, bearophile -- http://mail.python.org/mailman/listinfo/python-list
Don't use __slots__! (was Re: dicts vs classes)
In article <[EMAIL PROTECTED]>, Marc 'BlackJack' Rintsch <[EMAIL PROTECTED]> wrote: >In <[EMAIL PROTECTED]>, Guyon Morée >wrote: >> >> I'm using simple classes as a container of named values and I'm >> instantiating a lot of them in a very short time. >> >> i was wondering if there is any benefit in using dicts instead from a >> performance/memory usage point of view? > >If you really have a memory problem read the documentation about >`__slots__`. But I would only consider this if `a lot of` is several 100k >or millions of objects and the memory consumption really is a problem. Guido sez: __slots__ is a terrible hack with nasty, hard-to-fathom side effects that should only be used by programmers at grandmaster and wizard levels. Unfortunately it has gained an enormous undeserved popularity amongst the novices and apprentices, who should know better than to use this magic incantation casually. -- Aahz ([EMAIL PROTECTED]) <*> http://www.pythoncraft.com/ "Debugging is twice as hard as writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it." --Brian W. Kernighan -- http://mail.python.org/mailman/listinfo/python-list
Re: dicts vs classes
I'm wondering about whether to use objects in this way or dictionaries for a program I'm writing at the moment. It seems to me that unless you need some of the functionality supplied with dictionaries (len(a), has_key, etc) then simple objects are a syntacticaly cleaner and more natural way to express yourself. Any objctions to this, or pitfalls? Simon Hibbs -- http://mail.python.org/mailman/listinfo/python-list
Re: dicts vs classes
dict is already a classwhy another? Guyon Morée wrote: > Hi all, > > I'm using simple classes as a container of named values and I'm > instantiating a lot of them in a very short time. > > i was wondering if there is any benefit in using dicts instead from a > performance/memory usage point of view? > > regards, > > Guyon Morée > http://gumuz.looze.net > -- http://mail.python.org/mailman/listinfo/python-list
Re: dicts vs classes
"Guyon Morée" <[EMAIL PROTECTED]> writes: > I'm using simple classes as a container of named values and I'm > instantiating a lot of them in a very short time. > > i was wondering if there is any benefit in using dicts instead from a > performance/memory usage point of view? I recommend you to measure the time and memory usage for the two alternatives. That could give you the answer you want. HTH -- Marco Wahl http://visenso.com -- http://mail.python.org/mailman/listinfo/python-list
Re: dicts vs classes
In <[EMAIL PROTECTED]>, Guyon Morée wrote: > I'm using simple classes as a container of named values and I'm > instantiating a lot of them in a very short time. > > i was wondering if there is any benefit in using dicts instead from a > performance/memory usage point of view? If you really have a memory problem read the documentation about `__slots__`. But I would only consider this if `a lot of` is several 100k or millions of objects and the memory consumption really is a problem. Ciao, Marc 'BlackJack' Rintsch -- http://mail.python.org/mailman/listinfo/python-list
