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，启动代码后一切正常，它要求我按原样键入命令，如果我键入“ help”，它会按照预期运行要做的是列出所有命令，然后通过start（）命令将其重置，然后再次要求我输入命令，但是这次无论我写什么，都会激活此代码块：

 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，或解释为什么会发生这种情况吗？

谢谢你。

Answer 1

您必须在此处使用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']

Answer 2

您的代码有几个问题。这是一个有效的版本。

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


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


name = ""

while not name:
    command = start()

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

    # printing help for everything except add
    else:
        print("Here are the following commands for this program : ")
        i = 0
        for i in command_list:
            print(repr(i))

Answer 3

if (input == "help" or "Help"):
    print("Here are the following commands for this program : ")
    i = 0
    for i in command_list :
       print("'" + i + "'")
    start()  # <--- your call to start() function does not reset where the interpreter left off reading you code.

Python解释器仅读取您的每一行，并对其进行处理。在您的if语句中，行start()被调用，它要求用户输入并返回None。然后，如果此if语句完成，那么下一行将如您所述：

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

您的问题的解决方案：

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

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

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

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

   if input == "something for break condition":
       break

Answer 4

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Python输入问题？

4 个答案: