simple class question

[C GIllespie]

Dear all,

I'm new to both python and OOP, so could I ask a simple question.

I have class:

class species:
__init__(self,p op=0):
self.pop=pop

Now I want to do something like this:

X=species(pop=1 0)
Y=species(pop=X .pop)
OK, but now I want to update X.pop and have that mirrored in Y.pop, i.e. if
X.pop=5, Y.pop now equals 5.

What is the best/nicest/simplest way of doing this?

Many thanks

Colin

[Matt Grayson]

Re: simple class question

On Jan 20, 2004, at 12:34 PM, C GIllespie wrote:
[color=blue]
> Dear all,
>
> I'm new to both python and OOP, so could I ask a simple question.
>
> I have class:
>
> class species:
> __init__(self,p op=0):
> self.pop=pop
> Now I want to do something like this:
>
> X=species(pop=1 0)
> Y=species(pop=X .pop)
> OK, but now I want to update X.pop and have that mirrored in Y.pop,
> i.e. if
> X.pop=5, Y.pop now equals 5.
>
> What is the best/nicest/simplest way of doing this?[/color]

Instead of declaring Y as a new instance of species, just set Y equal
to X:

x = species(pop=10)
y = x
x.pop = 15
print y.pop
[color=blue]
>
> Many thanks
>
> Colin
>
>
> --
> http://mail.python.org/mailman/listinfo/python-list[/color]

------------------------------------------------
Matt Grayson

School of Information Sciences, University of Tennessee
-------------------------------------------------

[anton muhin]

Re: simple class question

C GIllespie wrote:[color=blue]
> Dear all,
>
> I'm new to both python and OOP, so could I ask a simple question.
>
> I have class:
>
> class species:
> __init__(self,p op=0):
> self.pop=pop
>
> Now I want to do something like this:
>
> X=species(pop=1 0)
> Y=species(pop=X .pop)
> OK, but now I want to update X.pop and have that mirrored in Y.pop, i.e. if
> X.pop=5, Y.pop now equals 5.
>
> What is the best/nicest/simplest way of doing this?
>
> Many thanks
>
> Colin
>
>[/color]

In some cases pop should be class attribute.

regards,
anton.

[Michael Spencer]

Re: simple class question

"anton muhin" <antonmuhin@ram bler.ru> wrote in message
news:bujsd7$iot 2m$1@ID-217427.news.uni-berlin.de...[color=blue]
> C GIllespie wrote:[color=green]
> > Dear all,
> >
> > I'm new to both python and OOP, so could I ask a simple question.
> >
> > I have class:
> >
> > class species:
> > __init__(self,p op=0):
> > self.pop=pop
> >
> > Now I want to do something like this:
> >
> > X=species(pop=1 0)
> > Y=species(pop=X .pop)
> > OK, but now I want to update X.pop and have that mirrored in Y.pop, i.e.[/color][/color]
if[color=blue][color=green]
> > X.pop=5, Y.pop now equals 5.
> >
> > What is the best/nicest/simplest way of doing this?
> >
> > Many thanks
> >
> > Colin
> >
> >[/color]
>
> In some cases pop should be class attribute.
>
> regards,
> anton.[/color]
Example using class attribute:
[color=blue][color=green][color=darkred]
>>> class species(object) :[/color][/color][/color]
.... pop = [0] #Must be mutable object
.... def __init__(self, pop = 0):
.... self.pop[0] = pop
....[color=blue][color=green][color=darkred]
>>> x = species(10)
>>> x.pop[/color][/color][/color]
[10][color=blue][color=green][color=darkred]
>>> y = species(5)
>>> y.pop[/color][/color][/color]
[5][color=blue][color=green][color=darkred]
>>> x.pop[/color][/color][/color]
[5][color=blue][color=green][color=darkred]
>>>[/color][/color][/color]