为什么我的函数被无限调用？

Question

i = 1
while i != 3:
  if i == 1:
    def main3():
      decision3 = str(input("Do you accept? (Yes or No)"))
      if decision3 == 'No':
          print("narration")
      elif decision3 == 'Yes':
          print("narration")
          i = 2
      else:
          print("Sorry, that is an invalid input. Please re-enter.")
          main3()
    main3()
  else:
      i = 3
      print("narration")

应该运行代码，并且如果决策三的输入不是Yes或No，则用户应该重新输入输入。每当我运行代码时，它都会无限地询问Decision3。

Answer 1

i的值永远不变，因此main3()被永久调用。

if i == 1:
    def main3():
      decision3 = str(input("Do you accept? (Yes or No)"))
      if decision3 == 'No':
          print("narration")
      elif decision3 == 'Yes':
          print("narration")
          i = 2  # <-- This does nothing to i outside of main3()!
      else:
          print("Sorry, that is an invalid input. Please re-enter.")
          main3()
    main3()  # <-- This is the problem!

i仅在main3()范围内更改，不能全局更改。

请注意，请勿将input()的返回值强制转换为字符串。已经是一个了。