Python 输入问题？

Question

name_list = []
command_list = ["Add" ,"Help"]

def start():
 input("Hello please type in a command : ")

start()

if (input == "help" or "Help"):
    print("Here are the following commands for this program : ")
    i = 0
    for i in command_list :
       print("'" + i + "'")
    start()


if (input == "Add" or "add" ):
 name = input("Insert name please : ")
 print("Welcome " + name)
 name_list.append(name)

所以这段代码给我带来了一些麻烦，在启动代码时一切正常，它要求我按应有的方式输入命令，如果我输入“帮助”，它就会完全按照预期执行要做的是列出所有命令，之后它应该通过 start() 命令重置并再次要求我输入命令，但是这次无论我写什么它都会激活这段代码:

 if (input == "Add" or "add" ):
 name = input("Insert name please : ")
 print("Welcome " + name)
 name_list.append(name) 

有人可以帮我解决这个问题或者解释为什么会这样吗？？

先谢谢你。

Answer 1

你必须在这里使用 while 循环，而且 repr(i) 比 "'"+ i + "'" 更有效:

name_list = []
command_list = ["Add" ,"Help"]

def start():
    return input("Hello please type in a command : ")

a=start()

while a.lower()=='help':
    print("Here are the following commands for this program : ")
    i = 0
    for i in command_list :
       print(repr(i))
    a=start()


if a.lower()=='add':
 name = input("Insert name please : ")
 print("Welcome " + name)
 name_list.append(name)
else:
 print('invalid input')

示例输出:

Hello please type in a command : help
Here are the following commands for this program : 
'Add'
'Help'
Hello please type in a command : Help
Here are the following commands for this program : 
'Add'
'Help'
Hello please type in a command : Add
Insert name please : Bob
Welcome Bob

还有:

print(name_list)

返回:

['Bob']