&vs * 和 |对比 + [英] & vs * and | vs +

问题描述

在进行 boolean 数组比较时，使用 & 代替 * 或 |<是否有任何优势/约定/code> 代替 +?这些总是等价的吗?

When doing boolean array comparison, is there any advantage / convention to using & in place of * or | in place of +? Are these always equivalent?

(如果这些在文档中，链接可能是可以接受的答案，但我对numpy &"和numpy elementwise boolean compare"的天真搜索没有产生任何相关的东西)

(if these are in the documentation, a link would probably be an acceptable answer, but my naive search for 'numpy ampersand' and 'numpy elementwise boolean comparison' didn't yield anything relevant)

推荐答案

在 numpy 中 & 和 | 等价于 np.bitwise_and 和 np.bitwise_or.您还可以将 ^ 用于 np.bitwise_xor.这都记录在算术和比较运算ndarray 文档的部分.np.logical_and 也有 ufunc，np.logical_or 和 np.logical_xor.

In numpy & and | are equivalent to np.bitwise_and and np.bitwise_or. You can also use ^ for np.bitwise_xor. This is all documented in the Arithmetic and comparison operations section of the ndarray docs. There are also ufuncs for np.logical_and, np.logical_or and np.logical_xor.

如果你的数组都是 dtype bool 应该没有任何区别.我个人倾向于 & 和 |，即使你对 bool dtype 不严格，它也会给你带来这样的麻烦:

If your arrays are all of dtype bool there shouldn't be any difference. I personally lean towards & and |, even though if you are not strict about the bool dtype it can get you in troubles like this:

In [30]: np.array(2) & np.array(1)
Out[30]: 0

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