# How to randomly select 2 rows

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lech king on 5 Oct 2020
Edited: lech king on 5 Oct 2020
Hi
I want to randomly select 2 rows of a matrix
The matrix may have an odd number of rows
How to randomly select these 2 rows
for example
Random numbers are inside the variable B
Select the rows accordingly with the numbers in the random variable
B=randperm(19)
No duplicate rows
In other words, if a row is selected, it will no longer be selected

Ameer Hamza on 5 Oct 2020
Edited: Ameer Hamza on 5 Oct 2020
You can use the output of randperm as index
M = rand(10, 5); % random matrix
rows = randperm(size(M,1), 2)
M_new = M(rows, :)

Andreas Bernatzky on 5 Oct 2020
This would be my solution:
myMat = rand(10,50);
[nRow,~] = size(myMat);
randomRows = round((nRow - 1).*rand(2,1) + 1); % from 1 to nRow
firstRandomRow = myMat(randomRows(1),:);
secondRandomRow = myMat(randomRows(2),:);

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