无法分配给操作员 [英] Can't assign to operator

问题描述

i = 0
num = 0
while i <= 1000:
    if i % 3 and i % 5 == 0:
        num + i = num <--- Adding Up Numbers Divisable by 3 & 5...
    i += 1
print num

错误:* 不能分配给运算符(第 5 行)

Error:* can't assign to operator (line 5)

推荐答案

您确定不想要:

num = num + i

或等效地:

num += i

?

请注意，使用 sum、range 和生成器表达式可以更轻松地完成此操作:

Note that this can be done a little easier using sum, range and a generator expression:

sum( x for x in range(0,1000,5) if x % 3 == 0 )
                            #^only take every 5th element (0, 5, 10, 15 ...)
                                    #^ Also only take elements divisible by 3

如果您打算仅在 python 2.x 上运行此代码，则可以将上述表达式中的 range 更改为 xrange.另外，在阅读其他人的代码时，有时您会看到 if x % 3 == 0 在这种类型的上下文中写成 if not x % 3，但我更喜欢第一个版本(对我来说似乎更明确一些).

If you're planning on running this code on only python 2.x, you can change range to xrange in the above expression. Also, when reading other people's code, you'll sometimes see if x % 3 == 0 written as if not x % 3 in this type of context, but I prefer the first version (it seems a little more explicit to me).

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