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How do i select random indicies from an array?

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ME
ME on 5 Mar 2015
Answered: Image Analyst on 5 Mar 2015
I have an array of 10 by 6. is there a way I can randomly select rows from this particular array and everything within it.

Accepted Answer

Image Analyst
Image Analyst on 5 Mar 2015
Let's say you have a 10-by-6 matrix m, and you want to select 7 rows at random and make sure there are no repeats. Do this:
m = randi(9, 10,6)
randomRows = randperm(size(m, 1), 7)
randomRows is the array of row numbers , not the actual 6 element rows themselves.

More Answers (1)

Joseph Cheng
Joseph Cheng on 5 Mar 2015
Edited: Joseph Cheng on 5 Mar 2015
yes, you can perform something like this. Lets say your 10 by 6 array is called A;
then to get the random row(s) you can do
A(randi(10,N,1),:)
where 10 is the number or rows in A (or you can do size(A,1) if you do not want to hard code 10), N is the number of random rows you want to select and the : selects all columns.
  2 Comments
ME
ME on 5 Mar 2015
yes I am looking for unique rows Thank you for that. how would I save the randomised array into another array or even get the generated random results to be displayed... sorry I am new to this

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