為什么python告訴我我的yes變量未定義？

Question

我用Python 2.7編寫了這個腳本：

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")

這是我得到的錯誤：

Traceback (most recent call last):

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

     if (answer) == yes:

NameError: name 'yes' is not defined

Answer 1

您沒有名為yes變量，
您想要做的是將用戶輸入與字符串"yes"

會像這樣：

if answer == "yes":
    # do stuff

答案旁邊也不需要括號。

Answer 2

answer是一個字符串，您應該使用answer == "yes"

Answer 3

您需要在字符串中輸入"或' yes並非"yes" ， no並非"no" 。

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

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

錯誤name 'yes' is not defined是因為解釋器正在查找名為yes的變量，因為單詞中沒有"或' 。如果您輸入"yes"則解釋器會將answer變量的值與字符串"yes" 。