這個問題在這里已經有了答案： 范圍規則的簡短描述？ (9 個回答) 在函式中使用全域變數 21 個回答 昨天關閉。
a = int(input("How many pizza would you like to order? ")) #line 1
def count_ordered_pizza():
if a==0:
print("Okay see u next time!")
elif a==1:
print(str(a) " pizza ordered.")
elif a>1:
print(str(a) " pizzas ordered.")
else:
print("Sorry that's impossible")
def reorder():
user_said= str(input('Do you wish to order again? State Y/N. '))
while user_said != "N":
a = int(input("How many pizza would you like to order? ")) #line 16
count_ordered_pizza()
reorder()
print('Bye!')
如果我執行此操作，則ainreorder()函式（第 16 行）不會替換aincount_ordered_pizza()函式（第 1 行）。這是為什么？
我認為它可以替換它們，因為變數已被覆寫，但如果我這樣做：
def reorder():
user_said= str(input('Do you wish to order again? State Y/N. '))
while user_said != "N":
a = int(input("How many pizza would you like to order? ")) #line 16
if a==0:
print("Okay see u next time!")
elif a==1:
print(str(a) " pizza ordered.")
elif a>1:
print(str(a) " pizzas ordered.")
else:
print("Sorry that's impossible")
reorder()
print('Bye!')
它顯示了正確的值。有人可以幫我嗎？先感謝您！
uj5u.com熱心網友回復：
如果global a在函式全域解釋中使用運算式， 則可以更改全域變數值
a = int(input("How many pizza would you like to order? ")) #line 1
def count_ordered_pizza():
if a==0:
print("Okay see u next time!")
elif a==1:
print(str(a) " pizza ordered.")
elif a>1:
print(str(a) " pizzas ordered.")
else:
print("Sorry that's impossible")
def reorder():
user_said= str(input('Do you wish to order again? State Y/N. '))
while user_said != "N":
global a
a = int(input("How many pizza would you like to order? ")) #line 16
count_ordered_pizza()
reorder()
print('Bye!')
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