PYTHON我做錯了什麼？循環和if語句

Question

我有這樣的代碼：

methods = ["SNMP", "SUDP","ESSYN", "SSYN", "HTTP"] 

print("Methods: {}".format(', '.join(methods))) 
method = input("Enter method: ") 
method = method.upper() 

while method != methods: 
    print("ERROR: Method unknown") 
    method = input("Enter method: ") 
    method = method.upper() 

if method in methods: 
    print("Method: {}".format(method)) 

print("" 
     "" 
     "") 

seconds = input("Enter length in seconds: ") 
    print("{} seconds".format(seconds)) 

，你可以看到我試圖從用戶那裏得到的答案則顯示答案，並繼續到下一個任務。但是如果答案不在方法列表中，我希望它再次提出這個問題。但我無法弄清楚如何。我現在使用的代碼給了我錯誤消息「錯誤：方法未知」，當它最終確實說：方法（用這裏的方法）它不會進入下一個任務。任何人都可以告訴我該做什麼或在這段代碼中出了什麼問題？

Answer 1

怎麼能

while method != methods: 

永遠做有意義嗎？

也許你想：

while method not in methods: 

Answer 2

methods = ["SNMP", "SUDP","ESSYN", "SSYN", "HTTP"] 

print("Methods: {}".format(', '.join(methods))) 
ans = None 
while ans is None: # when ans is set as method or any other value loop will stop asking for methods 
    method = input("Enter method: ") 
    if method.upper() in methods: 
     ans = method # when you set ans it will not ask again 
     print("Method: {}".format(method)) 
     # rest of code here.... even another while loop for your input 
    else: 
     print("ERROR: Method unknown")