[Tutor] Variables and Functions

[Tiger12506]

Okay. "Class" is not a module. It is a keyword that defines a new type. 
Similar to an integer, or a string. But in the case of a class, you define 
what happens when you add, subtract, open, close, etc. by defining "methods" 
of a class. A classic example is a car.

class Car:
  running = 0
  headlightson = 0
  driving = 0
  def start(self):
    self.running = 1
  def drive(self):
    self.driving = 1
  def opendoor(self):
    self.door = 1
  def closedoor(self):
    self.door = 0
  def turnonheadlights(self):
    self.headlightson = 1

In the case of your puzzle, it would roughly look like this->

class Sudoku:
    def creatpuzzle(self, which):
      self.puzzle = #whatever code it takes to make that list
    def emptypuzzle(self):
      #code that uses self.puzzle because it is accessible in all methods of 
the class

Just a rough guideline of what we mean when we say you can put all of your 
functions in a class and use a class variable (in this case... self.puzzle)



----- Original Message ----- 
From: "Devon MacIntyre" <macintyredev at gmail.com>
To: "Kent Johnson" <kent37 at tds.net>
Cc: <tutor at python.org>
Sent: Wednesday, November 28, 2007 8:51 PM
Subject: Re: [Tutor] Variables and Functions


> Hi,
>
> I have two functions, 'new_sudoku' and 'play_game'. In new_sudoku, I have 
> a
> pre-determined puzzle (I wasn't able to get a randomly generated puzzle
> working), as a matrix in the variable 'puzzle'. I imported the 'copy' 
> module
> and made a deep-copy of 'puzzle' to make 'new_puzzle', which randomly has
> 85% of the digits replaced by an empty string. Now that 'new_puzzle' is 
> only
> 15% filled with numbers, I use turtle to place the numbers on a grid that 
> I
> made (also with turtle). After the grid and 'new_puzzle' are generated, I
> ask the player if he/she wants to begin playing. If yes, then the function
> 'play_game' is started. Here, I'm going to let the player choose spots to
> input their own numbers to fill in the board. My problem is that I can't 
> get
> the variables 'puzzle' and 'new_puzzle' into that function (to be 
> compared)
> because they are not globally defined; only in 'new_sudoku' function. 
> Here's
> some selected code from my program:
>
> def swap_row(puzzle,row1,row2):
>    temp = puzzle[row1]
>    puzzle[row1] = puzzle[row2]
>    puzzle[row2] = temp
>
> def new_sudoku():
>    puzzle = [[1,2,3,4,5,6,7,8,9], \
>              [4,5,6,7,8,9,1,2,3], \
>              [7,8,9,1,2,3,4,5,6], \
>              [2,3,4,5,6,7,8,9,1], \
>              [5,6,7,8,9,1,2,3,4], \
>              [8,9,1,2,3,4,5,6,7], \
>              [3,4,5,6,7,8,9,1,2], \
>              [6,7,8,9,1,2,3,4,5], \
>              [9,1,2,3,4,5,6,7,8]]
>    num_of_swap = random.randint(10,20)
>    for i in range(num_of_swap):
>        row1 = random.randint(0,8)
>        row2 = random.randint(0,8)
>        if row1/3 == row2/3:
>            swap_row(puzzle,row1,row2)
>    new_puzzle = copy.deepcopy(puzzle)
>    sparseness = 0.85
>    for i in range(9):
>        for j in range(9):
>            if random.uniform(0,1) < sparseness:
>                new_puzzle[i][j] = ''
>
> def play_game():
>    '''
>    Here is where I need the variables 'puzzle' and 'new_puzzle' to be
> brought.
>    '''
>
> I read about the 'class' module, but am not sure on it's execution. I 
> really
> appreciate any time spent on my (simple) problem.
> Thanks in advance.
>
> On Nov 28, 2007 4:18 PM, Kent Johnson <kent37 at tds.net> wrote:
>
>> Devon MacIntyre wrote:
>> > Hi,
>> > Just wondering, how would I get a variable out of one function and into
>> > another?
>>
>> I don't understand your description of your situation, maybe you could
>> show a little code as a simple example?
>>
>> The usual way to get a variable out of a function is to return a value
>> from the function. The usual way to get a variable into a function is to
>> pass a parameter. If you want tighter coupling than that maybe you
>> should make the functions into methods of a class and make the variables
>> into instance attributes.
>>
>> HTH,
>> Kent
>>
>


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