Re: [Tutor] samples on sort method of sequence object.
Lie Ryan, 14.01.2010 01:47: On 01/14/10 06:56, Hugo Arts wrote: On Wed, Jan 13, 2010 at 8:21 PM, Stefan Behnel stefan...@behnel.de wrote: Hugo Arts, 13.01.2010 15:25: Here is my solution for the general case: from itertools import groupby def alphanum_key(string): t = [] for isdigit, group in groupby(string, str.isdigit): group = ''.join(group) t.append(int(group) if isdigit else group) return t Note that this won't work in Py3, where integers and strings are not ordered, i.e. not comparable w.r.t the and operators. True. You can accommodate by writing a ComparableInt class extending int, and implement __lt__ and __gt__. It's not exactly succinct, but it works. Not necessary, you can just pass the cmp= parameter to sort that checks the chunk's type. Note that this won't work in Py3, where the cmp parameter is gone. Stefan ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] samples on sort method of sequence object.
On Thu, Jan 14, 2010 at 10:13 AM, Stefan Behnel stefan...@behnel.de wrote: Note that this won't work in Py3, where the cmp parameter is gone. Stefan And he's right again. I should've checked for that. Well, that makes a CmpInt class the only other solution: class CmpInt(int): def __lt__(self, other): if isinstance(other, str): return True return int.__lt__(self, other) def __gt__(self, other): if isinstance(other, str): return False return int.__gt__(self, other) Hugo ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Keeping a list of attributes of a certain type
(You top-posted, which puts your two comments out of order. Now the solution comes before the problem statement) Guilherme P. de Freitas wrote: Ok, I got something that seems to work for me. Any comments are welcome. class Member(object): def __init__(self): pass class Body(object): def __init__(self): self.members = [] def __setattr__(self, obj, value): if isinstance(value, Member): self.members.append(obj) object.__setattr__(self, obj, value) else: object.__setattr__(self, obj, value) def __delattr__(self, obj): if isinstance(getattr(self, obj), Member): self.members.remove(obj) object.__delattr__(self, obj) else: object.__delattr__(self, obj) john = Body() john.arm = Member() print(john.members) del john.arm print(john.members) On Wed, Jan 13, 2010 at 6:24 PM, Guilherme P. de Freitas guilhe...@gpfreitas.com wrote: Hi everybody, Here is my problem. I have two classes, 'Body' and 'Member', and some attributes of 'Body' can be of type 'Member', but some may not. The precise attributes that 'Body' has depend from instance to instance, and they can be added or deleted. I need any instance of 'Body' to keep an up-to-date list of all its attributes that belong to the class 'Member'. How do I do this? Best, Guilherme -- Guilherme P. de Freitas http://www.gpfreitas.com If this is a class assignment, you've probably got the desired answer. But if it's a real-world problem, there are tradeoffs, and until those are known, the simplest solution is usually the best. Usually, what's desired is that the object behaves as if it has an up-to-date list of... If order of the list doesn't matter, I'd consider simply writing a single method, called 'members' which does a list comprehension of the object's attributes, calculating the list when needed. Then use a decorator to make this method look like a read-only data attribute (untested): class Body (object): @property def members(self): return [obj for . if ] DaveA ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Keeping a list of attributes of a certain type
On Wed, Jan 13, 2010 at 9:24 PM, Guilherme P. de Freitas guilhe...@gpfreitas.com wrote: Hi everybody, Here is my problem. I have two classes, 'Body' and 'Member', and some attributes of 'Body' can be of type 'Member', but some may not. The precise attributes that 'Body' has depend from instance to instance, and they can be added or deleted. I need any instance of 'Body' to keep an up-to-date list of all its attributes that belong to the class 'Member'. How do I do this? If you want to keep track of attributes as they are added and deleted, you should override __setattr__() and __delattr__() in your Body class. http://docs.python.org/reference/datamodel.html#customizing-attribute-access Here is a simple example: In [4]: class LogAttributes(object): ...: def __setattr__(self, name, value): ...: print 'setting', name, 'to', value, type(value) ...: object.__setattr__(self, name, value) ...: def __delattr__(self, name): ...: print 'removing', name ...: object.__delattr__(self, name) In [5]: l = LogAttributes() In [6]: l.foo = 'bar' setting foo to bar type 'str' In [7]: l.foo Out[7]: 'bar' In [8]: del l.foo removing foo Kent ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Keeping a list of attributes of a certain type
On Wed, Jan 13, 2010 at 11:15 PM, Guilherme P. de Freitas guilhe...@gpfreitas.com wrote: Ok, I got something that seems to work for me. Any comments are welcome. class Member(object): def __init__(self): pass class Body(object): def __init__(self): self.members = [] def __setattr__(self, obj, value): if isinstance(value, Member): self.members.append(obj) object.__setattr__(self, obj, value) else: object.__setattr__(self, obj, value) That's fine but there is no need to duplicate the object.__setattr__() call: def __setattr__(self, obj, value): if isinstance(value, Member): self.members.append(obj) object.__setattr__(self, obj, value) def __delattr__(self, obj): if isinstance(getattr(self, obj), Member): self.members.remove(obj) object.__delattr__(self, obj) else: object.__delattr__(self, obj) Same here. Kent ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] looking for tutor
I have a decent amount of knowledge with QBASIC and am looking for a tutor who can help me learn the pythonic equivalent of QBASIC features and commands such as COLOR, LOCATE, IF...THEN, GOTO, loops, etc. as well as visual things and objects, which arent available in QBASIC (due to it being mostly text oriented). I would really appreciate this, as I am greatly enjoying learning python so far, but I really really need someone to help me along. thanks! -maxwell _ Your E-mail and More On-the-Go. Get Windows Live Hotmail Free. http://clk.atdmt.com/GBL/go/196390709/direct/01/___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Searching in a file
On Wed, 13 Jan 2010 23:05:11 - Alan Gauld alan.ga...@btinternet.com wrote: But a third option is to use a split and apply it to the whole file as a string thereby breaking the file into as many chunks as start with a line containing 'NEW'... Why not simply a regex pattern starting with NEW and ending with '\n'? import re pat = re.compile(NEW(.+)\n) source = abc\defNEWghi\njkl\nmno\nNEWpqr\nstu\n print pat.findall(source) # == ['ghi', 'pqr'] Denis la vita e estrany http://spir.wikidot.com/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Keeping a list of attributes of a certain type
On Wed, 13 Jan 2010 20:15:21 -0800 Guilherme P. de Freitas guilhe...@gpfreitas.com wrote: Ok, I got something that seems to work for me. Any comments are welcome. class Member(object): def __init__(self): pass class Body(object): def __init__(self): self.members = [] def __setattr__(self, obj, value): if isinstance(value, Member): self.members.append(obj) object.__setattr__(self, obj, value) else: object.__setattr__(self, obj, value) def __delattr__(self, obj): if isinstance(getattr(self, obj), Member): self.members.remove(obj) object.__delattr__(self, obj) else: object.__delattr__(self, obj) Seems perfectly ok to me, except for if...else constructs in place of simple if's: an optional statement is added in case obj is of type Member; this is not an alternative. if isinstance(value, Member): self.members.append(obj) object.__setattr__(self, obj, value)# in both cases Same for __delattr__, indeed. Denis la vita e estrany http://spir.wikidot.com/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] looking for tutor
On Wed, Jan 13, 2010 at 11:58 PM, maxwell hansen maxwellhan...@hotmail.comwrote: I have a decent amount of knowledge with QBASIC and am looking for a tutor who can help me learn the pythonic equivalent of QBASIC features and commands such as COLOR, LOCATE, IF...THEN, GOTO, loops, etc. as well as visual things and objects, which arent available in QBASIC (due to it being mostly text oriented). I would really appreciate this, as I am greatly enjoying learning python so far, but I really really need someone to help me along. thanks! Well, there are lots of online tutorials available - at python.org if you click documentation, and then there are several contributors to this list who have also written tutorials. And then if you get stuck or need help understanding something, if you ask on this list, someone will usually have some insight. HTH, Wayne -- To be considered stupid and to be told so is more painful than being called gluttonous, mendacious, violent, lascivious, lazy, cowardly: every weakness, every vice, has found its defenders, its rhetoric, its ennoblement and exaltation, but stupidity hasn’t. - Primo Levi ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Searching in a file
spir denis.s...@free.fr wrote But a third option is to use a split and apply it to the whole file as a string thereby breaking the file into as many chunks as start with a line containing 'NEW'... Why not simply a regex pattern starting with NEW and ending with '\n'? Because I understood the OP had to extract the info from the lines *following* the one with NEW. You could mess around with match object stat positions etc but split seemed a much easier solution. Alan G ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Keeping a list of attributes of a certain type
Guilherme P. de Freitas guilhe...@gpfreitas.com wrote Here is my problem. I have two classes, 'Body' and 'Member', and some attributes of 'Body' can be of type 'Member', but some may not. The precise attributes that 'Body' has depend from instance to instance, and they can be added or deleted. I need any instance of 'Body' to keep an up-to-date list of all its attributes that belong to the class 'Member'. How do I do this? Check the type of the attribute? Using isinstance()? I'm not sure of the rationale - why it needs to know the type etc But isinstance is the most obvious way that I can think of. Alan G. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] looking for tutor
maxwell hansen maxwellhan...@hotmail.com wrote I have a decent amount of knowledge with QBASIC and am looking for a tutor who can help me learn the pythonic equivalent of QBASIC features and commands The original version of my tutor was based on QBASIC and Python(v1.5!) It might still be useful for comparisons. The latest version uses VBScript which is somewhat similar to QBASIC... http://www.freenetpages.co.uk/hp/alan.gauld/oldtutor/index.htm -- Alan G Author of the Learn to Program web site http://www.alan-g.me.uk/l2p/ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] looking for tutor
maxwell hansen wrote: I have a decent amount of knowledge with QBASIC and am looking for a tutor who can help me learn the pythonic equivalent of QBASIC features and commands such as COLOR, LOCATE, IF...THEN, GOTO, loops, etc. as well as visual things and objects, which arent available in QBASIC (due to it being mostly text oriented). I would really appreciate this, as I am greatly enjoying learning python so far, but I really really need someone to help me along. thanks! -maxwell May I suggest ( http://inventwithpython.com/ ) that features Graphics and Animation in Chapter 16. Ken ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Searching in a file
On 01/14/10 10:29, Hugo Arts wrote: On Thu, Jan 14, 2010 at 12:05 AM, Alan Gauld alan.ga...@btinternet.com wrote: I prefer the next() approach. Rightfully so. IMO, The while loop with readline is basically the C version of that, for the poor people who don't have iterators. I would often prefer while loop with next() though. Writing a state machine with for-loop can become quite messy because of the implicit next() on each iteration. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
