警告:为操作员和驾驶员执行的Matlab式短路操作 [英] warning: Matlab-style short-circuit operation performed for operator &

问题描述

代码:

if (round(xw(1))>2) & (round(xw(2))>2) & (round(xw(1))<h-1) & (round(xw(2))<w-1)
        W0 = img(round(xw(1))-2:round(xw(1))+2,round(xw(2))-2:round(xw(2))+2);
else
        NA=1;
        break
endif

xw是包含点坐标的列向量. h和w是图像的尺寸.

xw is a column vector which contains the co-ordinates of a point. h and w are the dimensions of an image.

我正在 OCTAVE

但是当我运行包含这些行的函数时，我会得到警告

But when I run the function which contains these lines I get a warning

warning: Matlab-style short-circuit operation performed for operator &

是不是使用&，但 octave 仍在执行&&操作?

Is it that in spite of using &, octave is performing && operation?

我了解到，如果我使用&&，则根据第一条语句是True还是False，将评估下一条语句.

I learnt that if I use && then depending on the first statement is True or False, the next statements are evaluated.

那么，当我收到此警告时，这是怎么回事?那么该问题的解决方案是什么?

So, is this what is happening when I get this warning? What is the solution to this problem then?

我想检查所有语句是否都是True而不仅仅是第一个.

I want to check if all the statements are True and not just the first one.

推荐答案

通过使用&&运算符可以安全地避免该警告.

You can safely avoid the warning by using && operator instead.

警告来自 Matlab具有特殊处理方式对于&运算符，在这种情况下:

The warning comes from the fact that Matlab has a special handling for & operators in this context:

当您使用元素级&和|上下文中的运算符 if或while循环表达式(仅在该上下文中)，它们使用 短路以评估表达式.

When you use the element-wise & and | operators in the context of an if or while loop expression (and only in that context), they use short-circuiting to evaluate expressions.

出于兼容性的原因，Octave会检测到此行为并模拟Matlab的行为.请注意，在Matlab中也完全可以使用&&，因为无论如何这都是隐式使用的.

For reasons of compatibility, Octave detects this behaviour and emulates what Matlab does. Note that its completely safe to use && also in Matlab since that is what is implicitly used anyways.

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