Re: Index expressions: .* vs &

[c.]

On 6 Aug 2010, at 07:55, Mike B. wrote:

> Hi All,
>
> Can someone please explain the following behaviour:
>
> a = [1; 2 ];
> z1 = (a > 0)&(a>1);
> z2( z1 ) = 1
>
> gives z2 = [ 0, 1 ] (as expected).
>
> Now,
> z1 = (a > 0).*(a>1);
> z2( z1 ) = 1
>
> gives
> > error: subscript indices must be either positive integers or  
> > logicals.
>
> why the difference between & and .* when used for index expressions?
>
> Thanks,
> Mike.

That is because:

--------------------
>> a = [1; 2 ];
>> z1 = (a > 0).*(a>1);
>> class (z1)
ans = double
--------------------

while

--------------------
>> z1 = (a > 0) & (a>1);
>> class (z1)
ans = logical
--------------------

HTH,
c.