Total beginner wrote a tic tac toe game in Python and would like some feedback

Question

I've decided to learn Python about 2 weeks ago, been going through various books and videos, and I've decided to try my hand at programming a tic tac toe game. I was somewhat successful (it doesn't recognize if there's already a mark in a certain spot and allows overwriting of already placed marks) and I was wondering if any more experienced programmers could give me some general feedback about how I could do things better. Thank you so much and I hope you're all staying safe.

board = ['-'] * 9

def print_board():
    print (board[0] + '|' + board[1] + '|' + board[2])
    print (board[3] + '|' + board[4] + '|' + board[5])
    print (board[6] + '|' + board[7] + '|' + board[8])




legalMoves = [1,2,3,4,5,6,7,8,9]
print_board()

turnCount = 0
def move():



    move = int(input('Pick a number 1-9:'))
    while move not in legalMoves:
        print('Illegal move')
        move = int(input('Pick a number 1-9:'))



    marks = ['X','O']


    if turnCount % 2 == 0:
        board[move - 1] = marks[1]
    else:
        board[move - 1] = marks[0]



while True:
    if board[0] == board[1] == board[2] == 'X'
    or board[3] == board[4] == board[5] == 'X'
    or board[6] == board[7] == board[8] == 'X'
    or board[0] == board[3] == board[6] == 'X'
    or board[1] == board[4] == board[7] == 'X'
    or board[2] == board[5] == board[8] == 'X'
    or board[0] == board[4] == board[8] == 'X'
    or board[2] == board[4] == board[6] == 'X' 
    or board[0] == board[1] == board[2] == 'O' 
    or board[3] == board[4] == board[5] == 'O' 
    or board[6] == board[7] == board[8] == 'O' 
    or board[0] == board[3] == board[6] == 'O' 
    or board[1] == board[4] == board[7] == 'O' 
    or board[2] == board[5] == board[8] == 'O' 
    or board[0] == board[4] == board[8] == 'O':
        print('Victory')
        break

    else:
        move()
        print_board()
        turnCount = turnCount + 1

Answer 1

well you need to check if the user has typed an int or something else, so that breaks your program, also prevent the user from overwriting existed cell input, also prevent the user from typing a number out of range which you have already taken care of that, so I have written this small function to give you the correct input and deals with wrong ones, you can use it

def isInt(strInt):
  for c in strInt:
    if c not in "0123456789": return False
  return True

def getNextMove():
  while True:
    moveStr = input("Pick a number 1-9: ") 
    if not isInt(moveStr): 
      print("Pls write only a number")
      continue
    move = int(moveStr)
    if move < 1 or move > 9: 
      print("Pls only 1-9 numbers are allowed")
      continue
    if board[move - 1] != "-":
      print("Pls choose an empty cell")
      continue
    return move

Well, if that helped, I couldn't stop my self from writing the full code for the game, I couldn't sleep anyway, so here it is, you may get some ideas, happy coding!

board = [" "] * 9
winner = ""

def printBoard():
  print("-" * 7)
  for i in range(3):
    print(f"|{board[i * 3]}|{board[i * 3 + 1]}|{board[i * 3 + 2]}|")
    print("-" * 7)

def isInt(strInt):
  for c in strInt:
    if c not in "0123456789": return False
  return True

def getNextMove():
  while True:
    moveStr = input("Pick a number 1-9: ") 
    if not isInt(moveStr): 
      print("Pls write only a number")
      continue
    move = int(moveStr)
    if move < 1 or move > 9: 
      print("Pls only 1-9 numbers are allowed")
      continue
    if board[move - 1] != " ":
      print("Pls choose an empty cell")
      continue
    return move

def checkHVD():
  for i in range(3):
    if board[i * 3] == board[i * 3 + 1] == board[i * 3 + 2] and board[i * 3] != " ":
      return board[i * 3]
    elif board[i] == board[i + 3] == board[i + 6] and board[i] != " ":
      return board[i]
  if (board[0] == board[4] == board[8] or board[2] == board[4] == board[6]) and board[4] != " ":
    return board[4]
  return False

for i in range(9):
  board[getNextMove() - 1] = i % 2 == 0 and "X" or "O"
  printBoard()
  winner = checkHVD();
  if winner:
    identity = winner == "X" and "first" or "second"
    print(f"The {identity} player({winner}) won")
    break

if not winner:
  print("It's a tie")