# how to select a random number from the existing matrix in each column

2 views (last 30 days)
PRANAY DISHAN on 7 Feb 2018
Commented: PRANAY DISHAN on 7 Feb 2018
Dear friends, I need to select a random number from each column from the existing matrix to create a new row as shown below: I'm new to matlab. So please help me with this. Thank you.
A=[1 2 3 4;5 6 7 8;9 10 11 12]
Anew=[5 2 7 12]

Roger Stafford on 7 Feb 2018
Edited: Roger Stafford on 7 Feb 2018
[m,n] = size(A);
Anew = A(randi(m,[1,n])+m*(0:n-1));

per isakson on 7 Feb 2018
Edited: per isakson on 7 Feb 2018
It's smarter to use a for-loop
>> A
A =
1 2 3 4
5 6 7 8
9 10 11 12
>> [nrow,ncol] = size(A);
>> ix = randi([1,nrow],[1,ncol])
ix =
3 1 3 1
>> A(sub2ind(size(A),ix,1:ncol))
ans =
9 2 11 4
PRANAY DISHAN on 7 Feb 2018
Thank you sir.It was very helpful.

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