Question

可能重复：
  python, basic question on loops
  how to let a raw_input repeat until I wanna quit?

我想要一些Python的帮助。

我在Py2.7.2中编写程序，但遇到了一些问题。

到目前为止我所拥有的是这样的：

choice = raw_input("What would you like to do")
 if choice == '1':
  print("You chose 1")
 elif choice == '2':
  print("You chose 2")
 elif choice == '3':
  print("You chose 3")
 else:
  print("That is not a valid input.")

但是在用户选择1,2,3或4之后，程序会自动退出。有没有办法可以让程序重新启动，以便再次询问它们“你想做什么？”;这样就会继续发生，直到用户退出程序。

Answer 1

您可以使用while循环完成此操作。更多信息： http://wiki.python.org/moin/WhileLoop

示例代码：

choice = ""

while choice != "exit":
    choice = raw_input("What would you like to do")
    if choice == '1':
        print("You chose 1")
    elif choice == '2':
        print("You chose 2")
    elif choice == '3':
        print("You chose 3")
    else:
        print("That is not a valid input.")

Answer 2

使用While Loop -

choice = raw_input("What would you like to do (press q to quit)")

while choice != 'q':
    if choice == '1':
        print("You chose 1")
    elif choice == '2':
        print("You chose 2")
    elif choice == '3':
        print("You chose 3")
    else:
        print("That is not a valid input.")
    choice = raw_input("What would you like to do (press q to quit)")

Answer 3

你需要一个循环：

while True:
  choice = raw_input("What would you like to do")
  if choice == '1':
      print("You chose 1")
  elif choice == '2':
    print("You chose 2")
  elif choice == '3':
    print("You chose 3")
  else:
    print("That is not a valid input.")

Answer 4

我个人建议你这样做。我会把它放到一个while循环中，main是你的程序然后它在第一个循环完成后运行exit语句。这是一种更简洁的方法，因为您可以编辑选项而无需担心必须编辑退出代码。：）

def main():
    choice=str(raw_input('What would you like to do?'))
    if choice == '1':
        print("You chose 1")
    elif choice == '2':
        print("You chose 2")
    elif choice == '3':
        print("You chose 3")
    else:
        print("That is not a valid input.")
if __name__=='__main__':
    choice2=""
    while choice2 != 'quit':
        main()
        choice2=str(raw_input('Would you like to exit?: '))
        if choice2=='y' or choice2=='ye' or choice2=='yes':
            choice2='quit'
        elif choice2== 'n' or choice2=='no':
            pass

Python - 循环输入

4 个答案: