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POMatlab: Search rows in matrix with fixed first and last element with vectorization
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copied!<p>I have a matrix like the following (arbitrary cols/rows):</p> <pre><code>1 0 0 0 0 1 2 0 0 0 1 2 3 0 0 1 2 3 4 0 1 2 3 4 5 1 2 5 0 0 1 2 5 3 0 1 2 5 3 4 1 4 0 0 0 1 4 2 0 0 1 4 2 3 0 1 4 2 5 0 1 4 2 5 3 1 4 5 0 0 1 4 5 3 0 2 0 0 0 0 2 3 0 0 0 2 3 4 0 0 2 3 4 5 0 2 5 0 0 0 2 5 3 0 0 2 5 3 4 0 3 0 0 0 0 3 4 0 0 0 3 4 2 0 0 3 4 2 5 0 3 4 5 0 0 </code></pre> <p>and now I want to get all rows where the first element is a certain value X and the last element (that is the last element != 0) is a certain value Y, OR turned around: the first is Y and the last is X.</p> <p>Can't see any speedful code which does NOT use a for-loop :( Thanks!</p> <p><strong>EDIT</strong>: To filter all rows with a certain first element is really easy, you don't need to help me here. So let's assume I only want to do the following: Filter all rows where the last element (i.e. the last element != 0 in each row) is either X or Y.</p> <p><strong>EDIT</strong> Thanks a lot for your posts. I benchmarked the three possible solutions with a matrix of 473408*10 elements. Here's the benchmarkscript: <a href="http://pastebin.com/9hEAWw9a" rel="nofollow">http://pastebin.com/9hEAWw9a</a></p> <p>The results were:</p> <pre><code>t1 = 2.9425 Jonas t2 = 0.0999 Brendan t3 = 0.0951 Oli </code></pre> <p>So thanks a lot you guys, I'm sticking with Oli's solution and thus accept it. Thanks though for all the other solutions!</p>

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