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PropagandaPanda

Oct 16 2009, 10:04 PM

Hello.

I'm having some trouble with arrays in Python. From what I understand, when a statement such as the one below is used, the NewArray does not contain a copy of the OldArray, but any references to NewArray are simply redirected to OldArray.

CODE

NewArray = OldArray

This is demontrated:

CODE

Array = [1,1,1,1,1,1]
Arr2 = Array
Array[0] = 99
print Arr2

returns [99, 1, 1, 1, 1, 1]

I can work around this by doing such.

CODE

Array = [1,1,1,1,1,1]
Arr2 = Array[:]
Array[0] = 99
print Arr2

This doesn't work when I want to call a function that has an array as an argument.

CODE

def MakeMove(Board,Rows,Marker,Move):
    Board = Board[:]
    for i in range(0,Rows):
        i = (Rows-1)-i
        if Board[i][Move]==".":
            Board[i][Move] = Marker
            break
    return Board

(Function from a connect 4 game)

Normally, I would use this to actually change the board, in which case it works well.

However, when I want to test a potential new move using this function, it still alters the argument passed to it.

For instance:

CODE

TestBoard = MakeMove(TheBoard[:],Rows,Marker,Move)

TheBoard variable is changed.

Is there some way to avoid this?

Thanks,
The Panda

Romeo29

Oct 17 2009, 09:08 AM

Try changing the variable names as shown in bold:

def MakeMove(Bord,Rows,Marker,Move):
Board = Bord[:]

PropagandaPanda

Oct 17 2009, 10:06 AM

Thanks, but I figured it out

QUOTE

import copy
MakeMove(copy.deepcopy(Board),Rows,Marker,Move):

I tried changing the variable name yesterday, but it didn't work.

With Regards,
The Panda

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