python - 尝试从函数分配时全局变量不起作用
问题描述
我正在学习 Python,但我遇到了 gobal 变量的问题。我已经全局定义了变量,然后使用global
关键字从函数中分配它们。但是,当它运行脚本时,它仍然无法分配变量。
看了这个解决方案,在函数中使用全局变量,我不知道为什么他的代码正在工作,而我的相同逻辑却失败了。无法弄清楚并在小问题上停留了几个小时。
def player_input():
player_1_name = input('Please enter your name Player 1.')
player_2_name = input('Please enter your name Player 2.')
player_1_symbol='None'
player_2_symbol=''
allowed_symbol=['X','O']
symbol_accepted = False
def get_symbol():
global player_1_symbol
player_1_symbol = input('Please enter your preferred symbol {}. It can be either X or O. '.format(player_1_name))
print('value of symbol after assignment: '+ player_1_symbol)
def validate_symbol():
global symbol_accepted
print('value of symbol when process started: '+ player_1_symbol)
if player_1_symbol.upper() in allowed_symbol:
print('it passed')
symbol_accepted = True
else:
print('it came here, because it did not find the value of player_1_symbol')
get_symbol()
while symbol_accepted == False:
validate_symbol()
if player_1_symbol.upper() == 'O':
player_2_symbol = 'X'
else:
player_2_symbol = 'O'
print("{}, unfortunately you don't have choice. You have been assigned the symbol {}.".format(player_2_name,player_2_symbol))
我想要达到的结果是我想assign player_1_symbol
从 get_symbol 函数中获取全局变量。也是如此symbol_accepted
。没有变量被分配。我正在打印它们,但我无法理解为什么它不起作用。我在 youtube 上看到了一些视频和一些文章。
我看到了其他一些关于输入验证的视频/文章,但是一旦我开始这个,我想了解它有什么问题,以便我global
将来可以使用。
解决方案
我用 player_symbols 创建了一个数组(player_1 为 0,player_2 为 1),因此可以正确分配变量。我还修复了 validate_symbol 重复的错误,因为 symbol_accepted 有相同的错误。
def player_input():
player_1_name = input('Please enter your name Player 1.')
player_2_name = input('Please enter your name Player 2.')
player_symbols = ["", ""]
allowed_symbol = ['X', 'O']
symbol_accepted = False
def get_symbol():
player_symbols[0] = input(
'Please enter your preferred symbol {}. It can be either X or O. '.format(player_1_name))
print('value of symbol after assignment: ' + player_symbols[0])
def validate_symbol(symbol_accepted):
print('value of symbol when process started: ' + player_symbols[0])
if player_symbols[0].upper() in allowed_symbol:
print('it passed')
symbol_accepted = True
else:
print('it came here, because it did not find the value of player_1_symbol')
get_symbol()
return symbol_accepted
while symbol_accepted == False:
symbol_accepted = validate_symbol(symbol_accepted)
if player_symbols[0].upper() == 'O':
player_symbols[1] = 'X'
else:
player_symbols[1] = 'O'
print("{}, unfortunately you don't have choice. You have been assigned the symbol {}.".format(player_2_name,
player_symbols[1]))
player_input()
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