Python把同一个对象循环赋值给另外一个变量，修改一个对象，其他对象也修改了

>>> row=['_'] * 3>>> board = []>>> for i in range(3):...     board.append(row)...>>> row['_', '_', '_']>>> board[['_', '_', '_'], ['_', '_', '_'], ['_', '_', '_']]>>> board[2][1]='A'>>> row['_', 'A', '_']>>> board[['_', 'A', '_'], ['_', 'A', '_'], ['_', 'A', '_']]  #3个子对象都被修改了>>>

 

如果不想复制对象，可以在循环赋值前初始化下被赋值的变量

>>> board = []>>> for i in range(3):...     row=['_'] * 3   #循环赋值前，初始化下变量...     board.append(row)...>>> board[['_', '_', '_'], ['_', '_', '_'], ['_', '_', '_']]>>> row['_', '_', '_']>>> board[2][0] = 'X'>>> board[['_', '_', '_'], ['_', '_', '_'], ['X', '_', '_']]>>> row['X', '_', '_']>>>