为什么&&运算符看起来不适用于Matlab / Octave？

Question

I'm playing around with some slightly modified Euler problems. The following code:

a=(0:1:999);
b=a(mod(a,5) == 0)

Appears to do the right thing. However with a slight modification:

a=(0:1:999);
b=a(mod(a,5) == 0 && mod(a,3) == 0)

I get

b=[](0x0)

What is happening here?

Answer 1

You want & instead of &&

The & operator performs an element-by-element AND between matrices, while the && operator performs a short-circuit AND between scalar values.