蟒蛇IF如果陈述不显示

Question

目前我正在掌握与Python，我试图产生一个小脚本，但我有一个IF语句的问题，理想情况下，我想它，如果用户输入一个“N “或”n“代表”否“，那么我喜欢这个句子显示”感谢您使用FinalGrade。再见。“然而，它只是回圈并反应，就好像我输入了“Y”，允许输入另一名学生。

继承人我的代码：

results = [] 
cont = 'y' or 'Y' 

print ("\n") 
print ("-----------------------------------------------------------------------------") 
print ("\n") 
Institution = str(input("Please Enter the Name of Your Insitution: ")) 

while cont=='y' or 'Y': 
    print ("\n") 
    print ("---------------------------------NEW STUDENT---------------------------------") 
    print ("\n") 
    Year = str(input("Please Enter the Year of the Student (For Example, 'Year 1/2/3/4'): ")) 
    print ("\n") 
    print ("-----------------------------------------------------------------------------") 
    print ("\n") 
    Student = str(input("Student Full Name: ")) 
    print ("\n") 
    Grade1 = int(input("Enter Student's First Term Grade: ")) 
    Grade2 = int(input("Enter Student's Second Term Grade: ")) 
    Grade3 = int(input("Enter Student's Third Term Grade: ")) 
    Grade4 = int(input("Enter Student's Fourth Term Grade: ")) 

    average = (Grade1+Grade2+Grade3+Grade4)/4 

    print ("\n") 
    print ("-----------------------------------------------------------------------------") 
    print ("\n") 
    print ("Total Grade Average: %G" % (average)) 

    passed_or_failed = "PASSED" 
    if average < 40: 
     passed_or_failed = 'FAILED' 
    results.append(passed_or_failed) 

    print ("\n") 
    print ("%s has: %s" % (Student, passed_or_failed)) 
    print ("\n") 

我有我的代码中的主要问题如下：

cont = input('Do you want to keep entering students? Y/N: ') 
if cont=='N' or 'n': 
    print ("\n") 
    print ("-----------------------------------------------------------------------------") 
    print ("\n") 
    print ("Thank you for using FinalGrade. Goodbye.") 

有没有办法解决这个问题？谢谢。

Answer 1

如果续== 'N' 或 'N'：

你需要做的要么：

if cont in "nN": 

或：

if cont in ["n", "N"]: 

甚至：

if cont.lower() == "n": 

写你有什么，你期望if cont=='N' or 'n':无法正确评估。 这基本上等于在说：

• 如果续是（ “N” 或 “n”），那么做点什么

注：的括号（ “N” 或 “n” ）;这将评估为True，然后您的 if语句变为：if cont == True:总是计算为True。

参见：

>>> cont = "Y" 
>>> if cont == "N" or "n": 
...  print "cont is N or n" 
... 
cont is N or n 

更新::

你也想改变你的代码结构有点，以及对这样的事情：

while True: 
    ... most of your code ... 

    cont = raw_input("Do you want to continue? (Y/N)") 
    if cont.lower() == "n": 
     break 

更新II ：来自您的意见这是一个comp lete您的程序的修正版本： ＃！在/ usr /斌/包膜蟒蛇

#FinalGrade 

results = [] 

print ("\n") 
print ("-----------------------------------------------------------------------------") 
print ("\n") 
Institution = str(input("Please Enter the Name of Your Insitution: ")) 

while True: 
    print ("\n") 
    print ("---------------------------------NEW STUDENT---------------------------------") 
    print ("\n") 
    Year = str(input("Please Enter the Year of the Student (For Example, 'Year 1/2/3/4'): ")) 
    print ("\n") 
    print ("-----------------------------------------------------------------------------") 
    print ("\n") 
    Student = str(input("Student Full Name: ")) 
    print ("\n") 
    Grade1 = int(input("Enter Student's First Term Grade: ")) 
    Grade2 = int(input("Enter Student's Second Term Grade: ")) 
    Grade3 = int(input("Enter Student's Third Term Grade: ")) 
    Grade4 = int(input("Enter Student's Fourth Term Grade: ")) 

    average = (Grade1+Grade2+Grade3+Grade4)/4 

    print ("\n") 
    print ("-----------------------------------------------------------------------------") 
    print ("\n") 
    print ("Total Grade Average: %G" % (average)) 

    passed_or_failed = "PASSED" 
    if average < 40: 
     passed_or_failed = 'FAILED' 
    results.append(passed_or_failed) 

    print ("\n") 
    print ("%s has: %s" % (Student, passed_or_failed)) 
    print ("\n") 

    cont = input('Do you want to keep entering students? Y/N: ') 

    if cont.lower() == "n": 
     print ("\n") 
     print ("-----------------------------------------------------------------------------") 
     print ("\n") 
     print ("Thank you for using FinalGrade. Goodbye.") 
     break 

采样运行：http://codepad.org/hvoYCXWL

注意，条件检查输入更多的数据被正确地缩进while循环的块中。这是重要。

Answer 2

if cont=='N' or 'n': 

应该

或者更好

if cont in [ 'N', 'n' ]: