我的程序不会把分数
我的程序不会把分数
提问于 2013-07-06 04:00:37
对于这个作业，我们应该用Python做一个类，在那里我们放3个分数，并且必须找出学生的平均分和成绩。它可以工作，但我有一个错误。当我输入一个整数(例如73)三次时，它会显示字母等级。但是，当我输入一个带有小数点的数字(例如83.7)三次时，它不会显示字母等级，这就是我们需要的数字。有没有办法让它在我输入带有小数的数字时显示分数？为什么它只对整数有效？
class grades:
def __init__(self,name,test1,test2,test3,avg):
self.name = name
self.test1 = test1
self.test2 = test2
self.test3 = test3
self.avg = avg
def getName(self):
return self.name
def getTest1(self):
return self.test1
def getTest2(self):
return self.test2
def getTest3(self):
return self.test3
def getAvg(self):
return self.avg
#main:
name = input("Enter the students name: ")
test1 = float(input("Enter the first score: "))
test2 = float(input("Enter the second score: "))
test3 = float(input("Enter the third score: "))
avg = float(test1 + test2 + test3) /3.0
grades1 = grades(name,test1,test2,test3,avg)
grades1.name
grades1.test1
grades1.test2
grades1.test3
grades1.avg
print("The student's name is:" ,grades1.name)
print(grades1.name +"'s test scores are:")
print("---------------------------:")
print("TEST1: \t\t\t",grades1.test1)
print("TEST2: \t\t\t",grades1.test2)
print("TEST3: \t\t\t",grades1.test3)
print(grades1.name +"'s average is: \t",grades1.avg)
##if avg <= 100.0 and avg >= 90.0:
## print(name +"'s grade is: \t A")
##elif avg <= 89.0 and avg >= 80.0:
## print(name +"'s grade is: \t B")
##elif avg <= 79.0 and avg >= 70.0:
## print(name +"'s grade is: \t C")
##elif avg <= 69.0 and avg >= 60.0:
## print(name +"'s grade is: \t D")
##elif avg <= 59.0 and avg >= 0.0:
## print(name +"'s grade is: \t E")
if avg >= 90.0 and avg <= 100.0:
print(name +"'s grade is: \t A")
elif avg >= 80.0 and avg <= 89.0:
print(name +"'s grade is: \t B")
elif avg >= 70.0 and avg <= 79.0:
print(name +"'s grade is: \t C")
elif avg >= 60.0 and avg <= 69.0:
print(name +"'s grade is: \t D")
elif avg >= 0.0 and avg <= 59.0:
print(name +"'s grade is: \t E")我之所以评论一年级的部分，是因为我尝试了这两种方法，但都没有成功。
这就是我尝试的方法，但小数没有成功。
Enter the students name: k
Enter the first score: 89.9
Enter the second score: 89.9
Enter the third score: 89.9
The student's name is: k
k's test scores are:
---------------------------:
TEST1: 89.9
TEST2: 89.9
TEST3: 89.9
k's average is: 89.90000000000002回答 3
Stack Overflow用户
发布于 2013-07-06 04:14:44
问题出在你的if上。当平均值在89和90、79和80之间时，你没有理由这样做。此外，除了第一个之外，您不需要任何and，因为之前的每个检查都将确认and再次检查的内容。您可以将大多数if缩短为单个条件。
if avg > 100 or avg < 0:
#check for out of range grades first
print('Grade out of range')
elif avg >= 90.0:
print(name +"'s grade is: \t A")
# if the elif is reached, we already know that the grade is below 90, because
# it would have been handled by the previous if, if it were >=90
elif avg >= 80.0:
print(name +"'s grade is: \t B")
elif avg >= 70.0: # other wise the previous check will have caught it
print(name +"'s grade is: \t C")
elif avg >= 60.0:
print(name +"'s grade is: \t D")
elif avg >= 0.0:
print(name +"'s grade is: \t E") # should this be 'F' instead of 'E'?就因为我是个好人;)
class Grades:
def __init__(self, name, *tests):
self.name = name
self.tests = list(tests)
@property
def avg(self):
return sum(self.tests)/len(self.tests)
@property
def letter_avg(self):
avg = self.avg
if avg > 100 or avg < 0:
raise ValueError('Grade out of range')
elif avg >= 90.0:
return 'A'
elif avg >= 80.0:
return 'B'
elif avg >= 70.0:
return 'B'
elif avg >= 60.0:
return 'D'
elif avg >= 0.0:
return 'F'
def __iter__(self):
return iter(self.tests)
def __getattr__(self, attr):
"""Allows access such as 'grades.test1' """
if attr.startswith('test'):
try:
num = int(attr[4:])-1
return self.tests[num]
except (ValueError, IndexError):
raise AttributeError('Invalid test number')
else:
raise AttributeError(
'Grades object has no attribute {0}'.format(attr))
def main():
name = input("Enter the students name: ")
test1 = float(input("Enter the first score: "))
test2 = float(input("Enter the second score: "))
test3 = float(input("Enter the third score: "))
grades1 = Grades(name, test1, test2, test3)
print("The student's name is:" , grades1.name)
print(grades1.name +"'s test scores are:")
print("---------------------------:")
for index, test in enumerate(grades1):
print('TEST{0}: \t\t\t{1}'.format(index, test))
print("{0}'s average is {1}".format(grades1.name, grades1.avg))
print("{0}'s average is \t {1}".format(grades1.name, grades1.letter_avg))
if __name__ == '__main__':
main()Stack Overflow用户
发布于 2013-07-06 04:11:23
您的if-elif语句没有涵盖所有可能的值。例如，如果平均值为89.5，则所有块都不会捕获它。解决这个问题的最简单方法是从if-elif语句中删除<=子句，因为它们是不必要的。
if avg >= 90.0:
print(name +"'s grade is: \t A")
elif avg >= 80.0:
print(name +"'s grade is: \t B")
elif avg >= 70.0:
print(name +"'s grade is: \t C")
elif avg >= 60.0:
print(name +"'s grade is: \t D")
else:
print(name +"'s grade is: \t E")Stack Overflow用户
发布于 2013-07-06 04:12:13
你遗漏了一些边界条件，例如89.9，79.7，像这样的平均值在你的程序中不会打印任何分数。
你需要这样的东西：
if avg >= 90.0 and avg <= 100.0:
print(name +"'s grade is: \t A")
elif avg >= 80.0 and avg < 90.0: #should be <90 not 89.0
print(name +"'s grade is: \t B")
elif avg >= 70.0 and avg < 80.0: #should be <80 not 79.0
print(name +"'s grade is: \t C")
elif avg >= 60.0 and avg < 70.0: #should be <70 not 69.0
print(name +"'s grade is: \t D")
elif avg >= 0.0 and avg < 60.0: #should be <60 not 59.0
print(name +"'s grade is: \t E")演示：
The student's name is: dfgd
dfgd's test scores are:
---------------------------:
TEST1: 89.9
TEST2: 89.9
TEST3: 89.9
dfgd's average is: 89.90000000000002
dfgd's grade is: B更新：
更简洁的解决方案是bisect模块：
import bisect
lis = [0,60,70,80,90,100]
grades = list('EDCBA')
ind = bisect.bisect_right(lis,avg) -1
print(name +"'s grade is: \t {}".format(grades[ind]))页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/17496099
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