MATLAB: How to select randomly

randomrandperm

Hello, I have an 10000 rows and 10 columns matrix. I want to select randomly 500 rows from this matrix. I want to ask you, randperm function is true for this purpose. How can I select 500 rows randomly from this matrix?

Best Answer

Random can be defined in two ways:
% A is your original matrix
Nrows = size(A,1) ; % number of rows
% Option 1: randomly select 500 UNIQUE(!) rows
idx = randperm(Nrows) ; 
idx = idx(1:500) ;
% Option 2: randomly select 500 rows 
idx = randi(Nrows,[Nrows 1]) ;
% and then ...
B = A(idx,:) ;
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