How do I call specific rows of a matrix?

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Isaac Knee
Isaac Knee 2015-5-15
评论： Isaac Knee 2015-5-16
I have a function who's output is a 1 dimensional array of random numbers i.e. rows = [1 2 5 19], how do I call those corresponding rows from a matrix i.e. A(1 2 5 19,:)? I understand how to do it step by step in the command window but I want a parent function to be able to call them no matter what they are or how many elements are in 'row'. I tried A(rows,:) but it returned "index exceeds matrix dimensions".

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Image Analyst
Image Analyst 2015-5-15
编辑：Image Analyst 2015-5-15
Not sure what you tried, but this works perfectly fine:
rows = [1 2 5 19]
A = randi(9, 25, 2) % Sample data.
output = A(rows,:) % Extract rows 1, 2, 5, and 19 only.
Of course when you say "A(1 2 5 19,:)" that implies that A is a 2D array, but you said you want "a function who's output is a 1 dimensional array of random numbers" so I'm not exactly sure what 1D column vector you want. What would you have for your 1D output?
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Walter Roberson
Walter Roberson 2015-5-15
what is size(A) and what is max(rows) ?
Is it possible that it should be a column index instead of a row index?
How was the index determined?
Isaac Knee
Isaac Knee 2015-5-16
I figured out the problem eventually, the rows I had calculated before had been indexed wrong and that's what caused the problem. Thanks for the help!

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