----------------------------- On Tue, Jan 20, 2015 4:44 PM CET Alan Gauld wrote:
>On 20/01/15 12:04, jarod...@libero.it wrote: >> Dear all, I continue to try to understand some code: >> class Tutto(): I think you need a new-style class wit property. "Return a property attribute for new-style classes (classes that derive from object)." https://docs.python.org/2/library/functions.html#property I recently discovered that properties are implemented with descriptors: https://docs.python.org/2/howto/descriptor.html >> def __init__(self): >> print "Ok" >> #@property >> def readsets(self,nome): >> self.nome = nome >> self._readsets = parse_tutto_readset_file(self.nome) >> return self._readsets >> >> Why If uncomment the decorator the code not work: > >My understanding of the @property decorator is that it is only for defining >read-only properties. In other wordss it expects you to use it like: > >t = Tutto() >myvar = t.readsets > >notice no parens and no parameters. > >If you want to read the data from a file I'd suggest making the file part of >the constructor and then use readsets as shown above: > >class Tutto: > def __init__(self, filename): > self.filename = filename > print 'ok' > @property > def readsets(self): Might be useful to insert the following here (?) if hasattr(self, "_readsets"): return self._readsets > self._readsets = parse_tutto_readset_file(self.nome) > return self._readsets > >p = Tutto("/home/mauro/Desktop/readset.csv") >var = p.readsets > > >I'd also question why you seem to have a function that has the class name in >its name? Should that function not be a method of the class? >Or is it part of some third party library perhaps? "tutto" means "everything"? Maybe FortyTwo would be a cool name. :-) >hth >-- Alan G >Author of the Learn to Program web site >http://www.alan-g.me.uk/ >http://www.amazon.com/author/alan_gauld >Follow my photo-blog on Flickr at: >http://www.flickr.com/photos/alangauldphotos > > >_______________________________________________ >Tutor maillist - Tutor@python.org >To unsubscribe or change subscription options: >https://mail.python.org/mailman/listinfo/tutor _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: https://mail.python.org/mailman/listinfo/tutor
