Python:当我运行代码时,为什么我的字符串不会返回或打印

Question

def the_flying_circus(Question = raw_input("Do you like the Flying Circus?")):
    if Question == 'yes':
        print "That's great!" 
    elif Question == 'no':
        print "That's too bad!"

我试图获取if表达式来运行代码并返回基于原始输入的字符串.每次我运行它时,问题会提示但是当我尝试输入"是或否"时它会给我这个错误:

    Traceback (most recent call last):
  File "C:\Users\ftidocreview\Desktop\ex.py", line 1, in <module>
    def the_flying_circus(Question = input("Do you like the Flying Circus?")):
  File "<string>", line 1, in <module>
NameError: name 'yes' is not defined
>>> 

Answer 1

您应该使用raw_input()而不是input()Python将用户输入解释为变量(这就是您获得的原因name 'yes' is not defined).

此外,您不应该使用raw_input()默认参数值,因为每当Python加载模块时都会对此进行求值.

考虑以下:

def the_flying_circus(Question=None):
    if Question is None:
        Question = raw_input("Do you like the Flying Circus?")
    if Question == 'yes':
        print "That's great!" 
    elif Question == 'no':
        print "That's too bad!"

虽然,我不得不说,上述功能的目的并不完全清楚,因为Question现在既可以是问题,也可以是用户的答案.如何将问题作为字符串传递并将结果分配给Answer？

def the_flying_circus(Question):
    Answer = raw_input(Question)
    if Answer == 'yes':
        print "That's great!" 
    elif Answer == 'no':
        print "That's too bad!"

最后,Python中的变量名称在开头没有大写,因此代码将成为:

def the_flying_circus(question):
    answer = raw_input(question)
    if answer == 'yes':
        print "That's great!" 
    elif answer == 'no':
        print "That's too bad!"