How to select values of array using the logical operator "OR"?

GOAL: Hi, I have an array A and want to build a new array B by selecting two or more values using the logical operator OR.

MY SOLUTION: I wrote the following lines:

A=[1 3 4 3 7 8 5 4 6 5]';
B= zeros(size(A));
for i = 1:numel(A) 
    if A(i) == 3 || 5;
       B(i) = A(i);       
    else
       B(i) = NaN;
    end
end

PROBLEM: The logical operator OR is not working. The array B is not correct because it is identical to array A. As a result I expected to see:

NaN

3

NaN

3

NaN

NaN

5

NaN

NaN

5

However, If I remove the logical operator OR, B is correct but does not include the value 5.

I wonder if someone could tell me what I'm doing wrong and how to correct these lines.

Thank you in advance for your attention

Emerson

[Andrei Bobrov]

B = nan(size(A));
i1 = any(abs(bsxfun(@minus,A(:),[3,5])) < eps(100),2);
B(i1) = A(i1);

Answer 1

[Image Analyst]

Try

if A(i) == 3 || A(i) == 5  % BTW, no trailing semicolon needed.

Or, better yet, try this vectorized way:

A = [1 3 4 3 7 8 5 4 6 5]'
indexesToReplace = A == 3 | A == 5
B = nan(size(A));
B(indexesToReplace) = A(indexesToReplace)

[Emerson De Souza]

Thank you Image Analyst, both suggestions worked well.

Wish you a nice evening

Emerson

[Image Analyst]

If your numbers are floating point, not integers, then you'd best use Andrei's code. Refer to the FAQ: http://matlab.wikia.com/wiki/FAQ#Why_is_0.3_-_0.2_-_0.1_.28or_similar.29_not_equal_to_zero.3F