python 2.7.3 while 循环

Question

我是 python 的新手。我需要反复循环，要求用户选择一个选项，然后运行命令并重复，直到用户选择退出。如果用户选择任何其他选项，程序必须不断要求他们选择一个值，直到他们选择正确的值。到目前为止，我的计划进行得并不顺利。如果可能的话，我想保留 while,if,elif 条件。有人可以提供帮助吗？非常感谢!

print """
How do you feel today?
1 = happy
2 = average
3 = sad
0 = exit program
"""

option = input("Please select one of the above options: ")
while option > 0 or option <=3:
    if option > 3:
        print "Please try again"
    elif option == 1:
        print "happy"
    elif option == 2:
        print "average"
    elif option == 3:
        print "sad"
    else:
        print "done"

Answer 1

break 命令将为您退出循环 - 然而，就开始控制流程而言，也不推荐这样做。但是请注意，用户永远无法输入新值，因此您将陷入无限循环。

也许试试这个:

running = True

while running:
    option = input("Please select one of the above options: ")
    if option > 3:
        print "Please try again"
    elif option == 1:
        print "happy"
    elif option == 2:
        print "average"
    elif option == 3:
        print "sad"
    else:
        print "done"
        running = False