Assigning value in python list-CodePudding

I tried to create a tic tac toe program with python list:

theBoard=[' '' '' ']*3
def userInput(board):
    loop=True
    while loop:
        userInput=input("Please enter (row,column)")
        row=int(userInput[0])
        column=int(userInput[2])
        if row<1 or row>3:
            print('[ERROR: Invalid Input]')
            loop=True
        elif column<1 or column>3:
            print('[ERROR: Invalid Input]')
            loop=True
        else:
            board[row-1][column-1]='X'
            loop=False

def drawBoard(board):
    #Function that prints out board
    print(board[0][0] ' | ' board[0][1] ' | ' board[0][2])
    print('---------')
    print(board[1][0] ' | ' board[1][1] ' | ' board[1][2])
    print('---------')
    print(board[2][0] ' | ' board[2][1] ' | ' board[2][2])
    print('---------')

userInput(theBoard)
drawBoard(theBoard)

Error I got: TypeError: 'str' object does not support item assignment

edit: sorry, i forgot to add the error line

I dont know why but the program mistook theBoard as a string rather than a list.

*A lot of people asked me to change theBoard=[' '' '' ']*3 to theBoard=[' ',' ',' ']*3 which i did however, I am still receiving the same error

CodePudding user response：

In the line

theBoard=[' '' '' ']*3

You are creating a list of size 9

in the line

board[row-1][column-1]

You are treating the list as if it is a 2d list

To make theBoard in to a 2d list try:

theBoard=[' ',' ',' ']
theBoard = [theBoard,theBoard,theBoard]

CodePudding user response：

Well, its not the program, its you who mistook string for a list. You declare the board as:

theBoard=[' '' '' ']*3

So, youre passing a single string (technically three strings, but passed as one, so for your comfort, theyre concatenated). Output is a list with three strings. Therefore, when you call theBoard[0][1] - you are trying to access the second character of the first string. And that is ok, but, as strings are immutable, changing it is not allowed.

Declaring board like below is pretty much what you wanted, but it still gives you one dimentional table (thereforo, you should access the last element by calling theBoard[8], and not theBoard[2][2]

theBoard=[' ',' ',' ']*3

If you want it to be two dimensional, try:

theBoard = [["","",""] for i in range(3)]