爲什麼這個python代碼錯了？

Question

我寫了一個腳本與Python 2.7，這是代碼：

name=raw_input("Hi im a PC, who are you?") 

print("Hi " + name + " how are you, are you good?") 

answer = raw_input("") 

if (answer) == yes: 
    print("That's good to hear") 
elif (answer) == no: 
    print("Oh well") 
else: 
    print("Sorry, you didnt answer the question properly, Please answer with a yes or no") 

這是我的錯誤：

 
Traceback (most recent call last): 

File "C:/Python27/programs/2", line 4, in 

    if (answer) == yes: 

NameError: name 'yes' is not defined 

Answer 1

你有沒有名爲yes，
變量您要什麼做的是用戶輸入比較字符串"yes"

這會是這樣的：

if answer == "yes": 
    # do stuff 

也沒有必要圍繞答案的括號。

Answer 2

answer是一個字符串，你要使用answer == "yes"

Answer 3

你需要把"或'在你的字符串。 yes不是"yes"，而no不是"no"。

#if (answer) == yes: 
if (answer) == "yes": 

#elif (answer) == no: 
elif (answer) == "no": 

錯誤name 'yes' is not defined是因爲解釋尋找一個叫做yes變量，因爲這個詞是沒有"或'。如果您編寫"yes"，解釋程序將比較answer變量的值與字符串"yes"。