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

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Emerson De Souza on 13 Sep 2012
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.
Emerson
Andrei Bobrov on 14 Sep 2012
B = nan(size(A));
i1 = any(abs(bsxfun(@minus,A(:),[3,5])) < eps(100),2);
B(i1) = A(i1);

Image Analyst on 13 Sep 2012
Edited: Image Analyst on 13 Sep 2012
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)
Image Analyst on 14 Sep 2012
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