新手循环问题

Question

我在尝试用Python（3）来完成下面的任务时脑子都快死了。请帮忙。在

编写一个循环来计算以下一系列数字的总和：1/30+2/29+3/27+⋯+29/2+30/1。在

for numerator in range(1, 31, 1):
    denominator = (31 - numerator)
    quotient = numerator / denominator
    print(quotient)

我能算出每一个的商，但不知道如何有效地求和。在

Answer 1

total = 0
for numerator in range(1, 31, 1):
    denominator = (31 - numerator)
    quotient = numerator / denominator
    print(quotient)
    total += quotient
print/return(total)

你可能还没有意识到答案。在

Answer 2

你快到了，我给你一些提示。在

# initialize a total variable to 0 before the loop

for numerator in range(1, 31, 1):
    denominator = (31 - numerator)
    quotient = numerator / denominator
    print(quotient)
    # update the total inside the loop (add the quotient to the total)

# print the total when the loop is complete

如果您想看到一个更具Python（idomatic）的解决方案，请参阅zhangxaochen的答案。；）

Answer 3

为了提高效率：

In [794]: sum(i*1.0/(31-i) for i in range(1, 31)) # i*1.0 is for backward compatibility with python2
Out[794]: 93.84460105853213

如果必须在循环中显式地执行此操作，请参见@Bill's hints；）