如何找到与i模m相等的最小正整数? [英] How do I find the smallest positive integer congruent to i modulo m?

问题描述

我有一个变量，它包含一个角度(以度为单位)，该角度可以为正，也可以为负.现在，我需要确保此数字仅在0到360之间.这个数字是双精度数.

I have a variable that holds an angle, in degrees, which can be both positive and negative. I now need to make sure that this number is between 0 and 360 only. The number is a double.

一个好的算法会是什么?简单地执行角度％360无效，因为负数最终仍然是负数.奖金指向最小的算法(又名Code Golf).

What would a nice algorithm for doing that be? Simply doing angle % 360 does not work, because negative numbers end up still being negative. Bonus points to the smallest algorithm (aka, Code Golf).

显然，这在不同的语言中是不同的.在ActionScript和JavaScript中，取模将返回+ m和-m之间的数字:

Apparently this is different in different languages. In ActionScript and JavaScript, modulo will return a number between +m and -m:

(-5) % 360 = -5

推荐答案

d = ((d % 360) + 360) % 360;

如果取模的值在-359到359之间，则将起作用.

will work if modulo gives you a value between -359 and 359.

我个人将其放在一个单独的函数中，因为它像罪恶一样丑陋.

I'd personally put this in a separate function since it's as ugly as sin.

def mymodulo(n,m):
    return ((n % m) + m) % m;

• 第一个模数的取值范围是-359至359.
• 该加法器将其增加到1到719之间.
• 第二个模将其带回您想要的范围，从0到359.

对于代码高尔夫球，包括Python中的换行符在内的29个字符:

For code golf, 29 characters including the newline in Python:

def f(n,m):return((n%m)+m)%m

并不是Python真正需要它:(-5)%360用该语言为您提供355:-)

Not that Python actually needs it: (-5)%360 gives you 355 in that language :-)

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