使用 While 循环 (Python) 计算 GPA

Question

GPA 或平均绩点的计算方法是将学生在课程中获得的绩点相加，然后除以总学分。单个课程的成绩点是通过将该课程的学分乘以取决于所获得成绩的适当因子来计算的：

  A receives 4 grade points

  B receives 3 grade points

  C receives 2 grade points

  D receives 1 grade point

  F receives 0 grade point

您的程序将有一个用于计算多个 GPA 的 while 循环和一个用于收集个人成绩的 while 循环（即嵌套的 while 循环）。

对于您的演示，将这两个课程组合的 GPA 计算到小数点后 2 位：

 First Case:                5 units of A           4 units of B           3 units of C

 Second Case:           6 units of A           6 units of B           4 units of C

这是我目前所拥有的......

todo = int(input("How many GPA's would you like to calculate? "))
while True: x in range (1, todo+1)
n = int(input("How many courses will you input? "))
totpoints = 0
totunits = 0

while True:  range(1, n+1)

grade = input("Enter grade for course: " )
if grade == 'A':
    grade = int(4)
if grade == 'B':
    grade = int(3)
if grade == 'C':
    grade = int(2)
if grade == 'D':
    grade = int(1)
if grade == 'F':
    grade = int(0)

units = int(input("How many units was the course? "))
totunits += units
points = grade*units
totpoints += points
GPA = totpoints / totunits

print("GPA is ", ("%.2f" % GPA))
print("total points = ", totpoints)
print("total units = ", totunits)    

我的问题是如何正确地合并 while 函数？我的代码运行不正确。

提前致谢。

Answer 1

关于 Python，您必须了解的第一件事就是缩进。因此，请确保正确缩进 while 块。 while 语句的语法如下：

while <condition>:
    do_something

如果条件为真，则执行 while 块内的代码。执行代码后，再次检查条件。如果条件仍然为真，它将再次执行该块，依此类推，直到条件为假。一旦条件为假，它就会退出 while 块并继续执行代码。

最后一件事，Python 不像其他编程语言那样具有 case 语句。但是您可以使用字典，例如，我定义了一个字典来将成绩映射到分数并从您的代码中删除 if 语句：

gradeFactor = {'A':4, 'B': 3, 'C':2, 'D':1, 'F':0}
todo = int(raw_input("How many GPA's would you like to calculate? "))
while todo: 
    n = int(raw_input("How many courses will you input? "))
    totpoints = 0
    totunits = 0
    while n:  
        grade = raw_input("Enter grade for course: " )
        units = int(raw_input("How many units was the course? "))
        totunits += units
        points = gradeFactor[grade]*units
        totpoints += points
        n -= 1
    GPA = float(totpoints) / totunits
    print("GPA is ", ("%.2f" % GPA))
    print("total points = ", totpoints)
    print("total units = ", totunits)
    todo -= 1