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copied!<p>I. I think <a href="https://stackoverflow.com/questions/2435018/two-arrays-defining-2d-coordinates-as-array-indices-in-matlab-octave">this recent SO question</a> on indexing is a very good question for an "expert".</p> <blockquote> <p>I have a 2D array, call it 'A'. I have two other 2D arrays, call them 'ix' and 'iy'. I would like to create an output array whose elements are the elements of A at the index pairs provided by x_idx and y_idx. I can do this with a loop as follows:</p> <pre><code>for i=1:nx for j=1:ny output(i,j) = A(ix(i,j),iy(i,j)); end end </code></pre> <p>How can I do this without the loop? If I do output = A(ix,iy), I get the value of A over the whole range of (ix)X(iy).</p> </blockquote> <p>II. Basic knowledge of operators like element-wise multiplication between two matrices (<code>.*</code>).</p> <p>III. Logical indexing - generate a random symmetric matrix with values from <code>0-1</code> and set all values above <code>T</code> to 0.</p> <p>IV. Read a file with some properly formatted data into a matrix (<code>importdata</code>)</p> <p>V. Here's <a href="https://stackoverflow.com/questions/2425066/matlab-comparing-all-elements-in-three-arrays">another sweet SO question</a></p> <blockquote> <p>I have three 1-d arrays where elements are some values and I want to compare every element in one array to all elements in other two.</p> <p>For example:</p> <pre><code>a=[2,4,6,8,12] b=[1,3,5,9,10] c=[3,5,8,11,15] </code></pre> <p>I want to know if there are same values in different arrays (in this case there are 3,5,8)</p> </blockquote> <p><strong>Btw</strong>, there's an excellent chance your interviewee will Google "MATLAB interview questions" and see this post :)</p>

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