How to remove element from a list in matrix?

Question

I'm trying to build Nim "mathematical game of strategy" in Python, I have problem with removing element from specific list from the matrix, I started with getting game mode from user and then start removing elements.

def RemoveMatches(Stacks,StackNum,Matches):  
    if not_empty(Stacks[StackNum]):
        lenStack=len(Stacks[StackNum])
        try:  
            val=int(Matches)
        except ValueError:
            print ("Wrong input,try only with numbers")
            return False
        if val>lenStack:
            print "try again with smaller number"
            return False
        else :
            for i in range(Matches):
                Stacks[StackNum].pop()
            return True
    else:
        print "Stack that you have chose is already empty,try other satck"
        return False  

Stacks is the matrix that i build in main.
StackNum number of list that i want to remove from it elements.
Matches number of elements that i want to remove.

There is another function called ManageGame which control user's input "if it's 2 players or 1, getting StackNum /Matches":

def ManageGame(Stack,gameMode):
    if gameMode=='2':
        while(lastDot(Stack)):
            stackNum,matchesNum=raw_input('select number of the Stack and number of Matches between 1-10. keep a space between two numbers:').split(' ')

            check=RemoveMatches(Stack,int(stackNum),int(matchesNum))
            if check:
                DrawStacks(Stack)
            else:
                print "try again."

lastDot(Stack) is a function which checks if the matrix has more then 1 Dot.

The problem is when I'm trying to remove number of elements from StackNum I get somthing like this:
from:

When I type StackNum=1,Matches=2 I get:

Somehow I remove 2 Dots from each matrix line, I cannot see the problem in my code.

Answer 1

The return in the line:

for i in range(Matches):
    Stacks[StackNum].pop()
    return True

is situated in the wrong location. you have to move it after the for . Otherwise, after the first iteration it will exit and not run all the iterations:

for i in range(Matches):
    Stacks[StackNum].pop()
return True

Answer 2

the problem here with the list l=[] ,here how I build my matrix:

l=[]
tmp=[]
for i in range(10):
    l.append('*')
for i in range(5):
    tmp.append(l)

python works with pointers so I'm appending same pointer for tmp, when I make a change to one of them the rest going to be the same .
Here how I did solve it :

for i in range(5):  
    tmp.append(10)  

When I want to pop an element I subtract Matches number.