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Getting a tuple to return values.

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Join Date: Jan 2009

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thehivetyrant thehivetyrant is offline

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Getting a tuple to return values.

Oct 25th, 2009

Evening there.
I need to return an (x,y) tuple of an object, This x,y will be used to help 1 object calculate where the other object is and move towards it.

My problem is that both the objects need to know the others' x,y.
(i'm unsure how to get the x,y of both the objects in one tuple and still tell them apart.)

While writing that i thought that maybe i put 4 values in the tuple say, x1,y1,x2,y2 and then for the 1st object call x1,y1 only and the same for object 2, would that work?

Also i thought tuples are not changable and hence after the objects move towards each other, the loop'll start again and check their x,y but the x,y will be the same wont it because tuples cant be changed?

am i right or am i missing some way around this?

Sorry if i'm unclear and i apologies for the long post, i sometime have ideas of solving things while i'm writing the problem out.
Gets your brain moving and all.

Cheers guys

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Join Date: Jun 2008

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slate

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Oct 25th, 2009

You can use the observer pattern.

 Help with Code Tags 
 Python Syntax (Toggle Plain Text) 
 
class Observed(object):
    def register_observer(self,observer):
        self.observer=observer
    def notify(self):
        self.observer.update(self)
 
class Observer(object):
    def update(self,other):
        print(self,"gets that ",other," has moved")
        #decide what to do
        pass
 
 
class Something(Observer,Observed):
    def __init__(self,x,y):
        self.x=x
        self.y=y
        #super(Something,self).__init__()
    def move_to(self,x,y):
        self.x=x
        self.y=y
        self.notify()
    def update(self,other):
        super(Something,self).update(other)
        if other.x<self.x: self.move_to(self.x-1,self.y)# or whatever
 
o1=Something(1,2)
o2=Something(5,4)
 
o1.register_observer(o2)
o2.register_observer(o1)
o1.move_to(1,2)
class Observed(object):
    def register_observer(self,observer):
        self.observer=observer
    def notify(self):
        self.observer.update(self)

class Observer(object):
    def update(self,other):
        print(self,"gets that ",other," has moved")
        #decide what to do
        pass


class Something(Observer,Observed):
    def __init__(self,x,y):
        self.x=x
        self.y=y
        #super(Something,self).__init__()
    def move_to(self,x,y):
        self.x=x
        self.y=y
        self.notify()
    def update(self,other):
        super(Something,self).update(other)
        if other.x<self.x: self.move_to(self.x-1,self.y)# or whatever

o1=Something(1,2)
o2=Something(5,4)

o1.register_observer(o2)
o2.register_observer(o1)
o1.move_to(1,2)

More detailed

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lukerobi

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Oct 26th, 2009

why not use a set for this?

 Help with Code Tags 
 Python Syntax (Toggle Plain Text) 
info = {'x1': 123, 'y1': 456, 'x2: 789, 'y2': 012}
 
info = {'x1': 123, 'y1': 456, 'x2: 789, 'y2': 012}

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thehivetyrant thehivetyrant is offline

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Oct 26th, 2009

I have heard sets are pretty much better than tuple but for this piece of code i am required to use tuples.
Doctor's orders.

Thanks slate i'll have a look that this observer's pattern and try to see if i can work out my issues from that.

I'll get back with my progress later today.

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thehivetyrant thehivetyrant is offline

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Oct 26th, 2009

I'm having problems with a beast of an error.
A Beast i tell you!

I'm going to try explaining it without pasting ALL my code.

i wrote my getPos like this:

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def getpos():
        r1 = x,y = 100,100
        r2 = x,y = 800,800

i get the error:

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Traceback (most recent call last):
    r1.step(r2.getPos()[0],r2.getPos()[1])
AttributeError: r2 instance has no attribute 'getPos'

thats quite a shortened down version, it might be enough.
The part that confuses me is the part in the error was written by my lecturer and therefore is correct.

I have defined getPos() for both r1 and r2 (my objects), so why do i get that error?
Any one got any clues? As i dont.

cheers

Last edited by thehivetyrant; Oct 26th, 2009 at 9:46 am.

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jlm699

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Oct 26th, 2009

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Originally Posted by thehivetyrant

Help with Code Tags

Python Syntax (Toggle Plain Text)
    def getpos():
        r1 = x,y = 100,100
        r2 = x,y = 800,800
def getpos(): r1 = x,y = 100,100 r2 = x,y = 800,800
i get the error:
Help with Code Tags

(Toggle Plain Text)
Traceback (most recent call last):
    r1.step(r2.getPos()[0],r2.getPos()[1])
AttributeError: r2 instance has no attribute 'getPos'
Traceback (most recent call last): r1.step(r2.getPos()[0],r2.getPos()[1]) AttributeError: r2 instance has no attribute 'getPos'
I have defined getPos() for both r1 and r2 (my objects), so why do i get that error?
Any one got any clues?

So if getpos() is a function for a class object, then you forgot the most important detail. The parameter self !

Your function should be defined as such:

 Help with Code Tags 
 python Syntax (Toggle Plain Text) 
    def getpos(self):
        r1 = x,y = 100,100
        r2 = x,y = 800,800
    def getpos(self):
        r1 = x,y = 100,100
        r2 = x,y = 800,800

But then again you're using r1 and r2 inside this function, which may indicate this isn't a class function at all. So in that case, you wouldn't use r2.getPos(), you should just use getPos().

Maybe you should post a little bit more code so that we have some context to go by.

Last edited by jlm699; Oct 26th, 2009 at 9:53 am.

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vegaseat

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DaniWeb's Hypocrite

Oct 26th, 2009

Check the spelling of getPos()

May 'the Google' be with you!

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thehivetyrant thehivetyrant is offline

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Oct 26th, 2009

oh fudge, i must have changed that by mistake with all my changing of code to try and fix the problem, i definetly had it as getPos before.

I changed it and i got the error that i remember seeing before i must have screwed it up... Progress! haha.

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r1.step(r2.getPos()[0],r2.getPos()[1])
TypeError: getPos() takes no arguments (1 given)

i've given 1 arguement for getPos which apprently shouldnt take one.
Is that my r1=x,y=100,100 thing? should i not give them the values of 100,100 and let them do by themselves?

Last edited by thehivetyrant; Oct 26th, 2009 at 10:00 am.

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jlm699

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Oct 26th, 2009

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Originally Posted by thehivetyrant

oh fudge, i must have changed that by mistake with all my changing of code to try and fix the problem, i definetly had it as getPos before.

I changed it and i got the error that i remember seeing before i must have screwed it up... Progress! haha.
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r1.step(r2.getPos()[0],r2.getPos()[1])
TypeError: getPos() takes no arguments (1 given)
r1.step(r2.getPos()[0],r2.getPos()[1]) TypeError: getPos() takes no arguments (1 given)

See my above post

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vegaseat

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#10

Oct 26th, 2009

Give it a little test ...

 Help with Code Tags 
 python Syntax (Toggle Plain Text) 
class RobotB:
    def getPos(self):
        self.r1 = x,y = 100,200
        self.r2 = x,y = 700,800
        return self.r1, self.r2
 
r2 = RobotB()
print r2.getPos()         # ((100, 200), (700, 800))
print r2.getPos()[1]      # (700, 800)
print r2.getPos()[1][0]   # 700
class RobotB:
    def getPos(self):
        self.r1 = x,y = 100,200
        self.r2 = x,y = 700,800
        return self.r1, self.r2

r2 = RobotB()
print r2.getPos()         # ((100, 200), (700, 800))
print r2.getPos()[1]      # (700, 800)
print r2.getPos()[1][0]   # 700