Need ideas and insights on a project...

**bartonc** · Dec 16 '06, 03:05 AM

Originally posted by true911m

We have 75 ball objects, which can be picked randomly by a machine, and which therefore need an awareness of being picked(), since no ball can come up twice in a game.

Actually, I believe that the machine is the object in question and that balls are data that it dispences. The machine (object) has a better chance of encapsulating awareness of which numbers have been dispensed than a ball does.

Originally posted by true911m

We have a scorecard grid with 25 square objects on it, and appropriate values for each column of the grid (B: 1-15,i:16-30, etc.), which are chosen randomly on each card. If we work with all 75 possible numbers (maybe not the best approach), each number needs to know if it's on the bingo card for this game, whether it's matched a number that's already been picked(), and whether it's a Freebie (middle square on the card - 'FREE' instead of a number)

Initial questions:

Can like objects be grouped by some mechanism such that changing an external parameter has them respond to that change, or do they each need to be iterated/manipulated each time to become "aware" of global changes? For example, a number is picked() - can the squares "know" if one matches the new number, or do I need to trigger each one to check?

I've got similar thoughts here. Going to look for some examples

Originally posted by true911m

Maybe I'm thinking in more of a parallel-thread mode here, one thread per object, which remains "active" during the game. Is that way out there? It's probably over my head at this point anyway.

Reel me in; tell me what you think.

Do you have Robin Dunn's book: wxPython in Action?

**true911m** · Dec 16 '06, 03:15 AM

Originally posted by bartonc

Actually, I believe that the machine is the object in question and that balls are data that it dispences. The machine (object) has a better chance of encapsulating awareness of which numbers have been dispensed than a ball does.

I've got similar thoughts here. Going to look for some examples

Do you have Robin Dunn's book: wxPython in Action?

I haven't read it all, just looked up a few things.

I'm not really interested in the GUI in particular, more the logic. If the GUI objects are easier to build/attach to than abstract code items, that's fine.

**true911m** · Dec 16 '06, 03:18 AM

The reason for the balls, instead of the machine, as objects is that I want to exercise multiple identical objects in action. JFYI.

**bartonc** · Dec 16 '06, 04:25 AM

Originally posted by true911m

The reason for the balls, instead of the machine, as objects is that I want to exercise multiple identical objects in action. JFYI.

Ok, I'll buy that. So if each ball instance needs to know which number was just picked() here's how I'd (almost) lay out the structure:

Code:

# I do this a bit differently, but Mr. Dunn says something like this:

class NumberDispenser(object):
    def __init__(self):
        self.clients = []

    def RegisterClient(self, client):
        self.clients.append(client)

    def UpdateClients(self, data):
        for client in self.clients:
            client.Update(data)     # This part I don't like:
                                    # having to know the name of the client function here

class NumberClient(object):
    def __init__(self, server, name):
        self.name = name
        server.RegisterClient(self)

    def Update(self, data):
        print self.name, data


if __name__ == "__main__":
    server = NumberDispenser()
    client1 = NumberClient(server, "client #1")
    client2 = NumberClient(server, "client #2")

    # call this in response to some event or whatever
    server.UpdateClients(6545)

**bartonc** · Dec 16 '06, 04:30 AM

Originally posted by true911m

I haven't read it all, just looked up a few things.

I'm not really interested in the GUI in particular, more the logic. If the GUI objects are easier to build/attach to than abstract code items, that's fine.

Actually, I don't use the GUI stuff from the book. I really like (and use similar design) the Model-View-Controler idea. There is also threading discussion toward the end.

**true911m** · Dec 16 '06, 07:03 PM

Originally posted by bartonc

Actually, I don't use the GUI stuff from the book. I really like (and use similar design) the Model-View-Controler idea. There is also threading discussion toward the end.

OK, that's not ringing any bells. Can you elaborate on this - what, where, refs?

**true911m** · Dec 16 '06, 07:24 PM

Originally posted by bartonc

Ok, I'll buy that. So if each ball instance needs to know which number was just picked() here's how I'd (almost) lay out the structure:

Code:

    def UpdateClients(self, data):
        for client in self.clients:
            client.Update(data)     # This part I don't like:
                                    # having to know the name of the client function here

...
if __name__ == "__main__":
    server = NumberDispenser()
    client1 = NumberClient(server, "client #1")  # <===
    client2 = NumberClient(server, "client #2")  # <===

Regarding that, my original thought, which is admittedly BASIC-esque, was to define an array where each element would become an instance. I don't know how to translate that here, but such a construct would alleviate much of the naming overhead. I guess it would also be redundant, since if I did that I wouldn't need the objects at all. :) But like I said, it's an academic exercise...

Can I use some form of eval() to create something like (this is just off the top of my head, trying to get the idea across):

Code:

varhdr = 'client'

for i in range(75):
    eval(varhdr+str(i)+' = NumberClient(server, "client #'+str(i)+'")')

Don't know if that's close to a proper use of eval; in SB we had a means of constructing dynamic lines of code like that so they could be reused, as in a loop.

This problem is what I was referring to when I mentioned a curiousity about how people would "group"cont rol of these objects.

Actually, the use of a class variable, as discussed in that other thread, may make sense here. Such as, when a number is picked,

Code:

NumberClient.LastPicked=32

for square in grid:
    # execute instance.CheckPicked code here
    # each instance of NumberClient class now has 
    # a self.LastPicked value of 32 to process against

**bartonc** · Dec 17 '06, 01:30 AM

Originally posted by true911m

Regarding that, my original thought, which is admittedly BASIC-esque, was to define an array where each element would become an instance. I don't know how to translate that here, but such a construct would alleviate much of the naming overhead. I guess it would also be redundant, since if I did that I wouldn't need the objects at all. :) But like I said, it's an academic exercise...

Can I use some form of eval() to create something like (this is just off the top of my head, trying to get the idea across):

Code:

varhdr = 'client'

for i in range(75):
    eval(varhdr+str(i)+' = NumberClient(server, "client #'+str(i)+'")')

Don't know if that's close to a proper use of eval; in SB we had a means of constructing dynamic lines of code like that so they could be reused, as in a loop.

This problem is what I was referring to when I mentioned a curiousity about how people would "group"cont rol of these objects.

Actually, the use of a class variable, as discussed in that other thread, may make sense here. Such as, when a number is picked,

Code:

NumberClient.LastPicked=32

for square in grid:
    # execute instance.CheckPicked code here
    # each instance of NumberClient class now has 
    # a self.LastPicked value of 32 to process against

A list comprehension is what you are looking for. A comprehension is a very handy tool when you don't need much stuff going on in a loop, but you do need elements appended to a list. This technique creates the list object and fills it in all at once. Notice, also, the C-line string formatting. I use it all the time.

Code:

class NumberDispenser(object):
    def __init__(self):
        self.clients = []

    def RegisterClient(self, client):
        self.clients.append(client)

    def UpdateClients(self, data):
        for client in self.clients:
            client.Update(data)     # This part I don't like:
                                    # having to know the name of the client function here

class NumberClient(object):
    def __init__(self, server, name):
        self.name = name
        server.RegisterClient(self)

    def Update(self, data):
        print self.name, data


if __name__ == "__main__":
    server = NumberDispenser()
    # list comprehension syntax uses [] on around the expession, generators use ()
    instanceList = [NumberClient(server, "client%d" %i) for i in range(5)]
    for inst in instanceList:
        print inst.name

**bartonc** · Dec 17 '06, 12:01 PM

The list comprehension here

Code:

instanceList = [NumberClient(server, "client%d" %i) for i in range(5)]

is equivalent to

Code:

instanceList = []
for i in range(5):
    instanceList.append(NumberClient(server, "client%d" %i))

which may be easier to read. I learned comprehensions so long ago that I have forgotten if the benefits actually outweigh the mashed syntax. If I get a break, I'll look it up and get back to you.

**true911m** · Dec 17 '06, 03:07 PM

Originally posted by bartonc

The list comprehension here

Code:

instanceList = [NumberClient(server, "client%d" %i) for i in range(5)]

is equivalent to

Code:

instanceList = []
for i in range(5):
    instanceList.append(NumberClient(server, "client%d" %i))

which may be easier to read. I learned comprehensions so long ago that I have forgotten if the benefits actually outweigh the mashed syntax. If I get a break, I'll look it up and get back to you.

Not sure what you're looking up, but I get the listcomp. That does what I was thinking; it didn't occur to me to use the inline string formatting to achieve the desired result.

**bvdet** · Dec 17 '06, 03:16 PM

I have a couple of simple thoughts on your Bingo project:
The balls could be a list.

Code:

x = random.sample(range(1, 26, 1),25)
>>> x
[17, 23, 12, 18, 9, 6, 13, 10, 24, 7, 15, 3, 22, 4, 11, 8, 2, 14, 20, 25, 1, 19, 16, 5, 21]

When it is time to select a ball, pop it from the list.

The 'game' could be a dictionary of lists. The dictionary keys are 'card1', 'card2',...... and each list would be filled randomly with unique numbers. When a number is selected, each player's card is scanned for a match, and if a match is found, the list position is set to False.

Code:

for card in dd.keys():
    if ball in dd[card]:
        dd['card1'][dd.['card1'].index(ball)] == False

After a match is found, a card scan method could be called to check for Bingo.

My contribution to this tread is probably be limited by my experience. I try to keep things simple. Most of the applications I have developed involve calculations in 3D space, manipulation of lists, dictionaries, tuples and strings, and reading/writing small data files. Classes incorporate instance variables and functions and sometimes methods when useful. Typically I do not modify instance data externally. I have a Python project coming up - add a steel angle brace between two structural steel beams. At the right time I'll start a thread on it.

Please keep this thead going - I want to know how it turns out.

Best Regards,
BV

ps - tru911m (Mark), Are you from Baltimore, MD? I detailed the structural steel for the Hippodrome PAC on N. Eutah a few years ago. Beautiful structure.

**true911m** · Dec 17 '06, 03:51 PM

Hi BV,

Yes, I'm a lifelong Baltimoron as we jokingly say. I remember the Hippodrome from its declining days as a moviehouse back in the 70s. It's great that that area is receiving some deserved attention to (at lease some of ) the irreplaceable structures there. It used to be the grand shopping mecca downtown, before malls and the burbs took over.

As for the bingo, I'm pretty straightforward myself. In fact I keep slipping off the path I've laid for myself, in that this project has the arbitrary requirement that these items use objects to accomplish the task, even though it can be directly handled without them.

I'm trying, through use, to exercise my understanding of the interactions and management of simple objects, and I really want to create a couple of classes (balls in machine, squares on the bingo card) that must be instantiated many times (75 numbers, 25 squares) to get the hang of dealing with them all.

In fact, one misconception I keep falling back to is that an 'object' is more like a 'bot' - as if each of these items takes up CPU on its own in a separate thread, and all I have to do is 'talk' to them like IRC bots or something. In fact, I know better, that I have to go 'process' each one based on some sort of event, but that's what I keep seeing in my head, and I'm trying to shake it.

**true911m** · Dec 19 '06, 12:05 AM

OK, getting a really basic start here. I apologize if any of this repeats -- until it clicks, I'm having some issues retaining a few things.

Based on Barton's tutorial on variables in classes, I just received an unexpected result. Here's a sample:

Code:

class BingoCard:
    def __init__(self):
        self.card=[]
    def FillGrid(self):
        for row in range(5):
            for col in range(5):
                self.card.append((row,col))  # replace tuples with objects
    def ShowGrid(self):
        print self.card

card=BingoCard()
card.FillGrid()
card.ShowGrid()
print card.card

I expected to need ShowGrid() to get at my generated bingo card. What I didn't expect is that the last line, print, will also display the grid.

Since self.card is defined in BingoCard.__ini t__, I thought it would be inaccessible from the outside world, but the output shows differently:

Code:

[(0, 0), (0, 1), (0, 2), (0, 3), (0, 4), (1, 0), (1, 1), (1, 2), (1, 3), (1, 4), (2, 0), (2, 1), (2, 2), (2, 3), (2, 4), (3, 0), (3, 1), (3, 2), (3, 3), (3, 4), (4, 0), (4, 1), (4, 2), (4, 3), (4, 4)]
[(0, 0), (0, 1), (0, 2), (0, 3), (0, 4), (1, 0), (1, 1), (1, 2), (1, 3), (1, 4), (2, 0), (2, 1), (2, 2), (2, 3), (2, 4), (3, 0), (3, 1), (3, 2), (3, 3), (3, 4), (4, 0), (4, 1), (4, 2), (4, 3), (4, 4)]

What am I forgetting?

**true911m** · Dec 19 '06, 12:15 AM

Originally posted by true911m

Not sure what you're looking up, but I get the listcomp. That does what I was thinking; it didn't occur to me to use the inline string formatting to achieve the desired result.

I'm still having my original dilemma on these results.

I see how the listcomp generates the strings, but how do I make each string result become the name of a variable that I use to instantiate my object, all "hands off"?

(I'm working on this part right now...)

Need ideas and insights on a project...

Need ideas and insights on a project...

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