[Tutor] Problems with a Class

thomas coopman thomas.coopman at gmail.com
Sat Jan 13 13:12:51 CET 2007

On Sat, 13 Jan 2007 01:08:53 +0100
Carlos <carloslara at web.de> wrote:

> Hello,
> I'm just about to finish my project, but something is causing me 
> trouble. I need to find out how to get some information out of the 
> genetic algorithm that Im using. This algorithm is generating some 
> coordinates for a collection of objects, until now I needed only the 
> final result of the process. But I discovered that the final
> information is not enough, I need to get some intermediate data to
> actualize the positions of the objects and then evaluate those
> positions.
> This is the area of the algorith that I think holds the info that I
> need:
> def evolve(self, generations = 100):
>         self.halt_reached = 0
>         for gen in range(generations):
>             #Changed.
>             print 'GEN:',gen, self.entities
>             self.do_mutation()
>             self.do_crossover()
>             print "Average fitness generation " + str(gen) + ": " + 
> str(self.avg_fitness())
>             if self.debug == 1:
>                 self.echo_fitness()
>             if self.halt >= 0:
>                 max_entity = self.get_max_fitness()
>                 fit = self.calc_fitness(max_entity)
>                 if fit >= halt:
>                     self.halt_reached = 1
>                     return [max_entity]
> The line marked as #Changed is what I changed,  with this I was able
> to print the info, but I'm sorry to say that I have no clue at how to
> apply something like return() that would give me this self.entities
> list. As you can see there is a for loop and I need the info every
> time that it gets updated by the loop.
> Hopefully I'm making myself clear and the info is enough.
> Thanks for your help in advance
> Carlos
> _______________________________________________
> Tutor maillist  -  Tutor at python.org
> http://mail.python.org/mailman/listinfo/tutor


when you call return, you return from the function so
when you have something like this:

def loop():
	for i in range(10):
		return i

print loop()

This will print just 0.

when you want to get all the numbers, you can't use return in the loop
you could save them in a list or something, and after the loop return
the list.

def loop():
	x = []
	for i in range(10):
	return x

print loop()

this will print a list with all the numbers.

I hope this is what you mean.


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