how to select random rows from a matrix?
64 visualizzazioni (ultimi 30 giorni)
Mostra commenti meno recenti
i have a matrix of size 10037 by 9.
please tell me how to select 1000 random rows from the matrix and save it as a mnew matrix in another variable.
thanks in advance.
0 Commenti
Risposte (2)
Andrei Bobrov
il 7 Ott 2011
m = rand(10037,9);
k = randperm(10037);
mnew = m(k(1:1000),:);
7 Commenti
Jan
il 24 Ott 2017
Or with the original order:
M = rand(10037,9);
k = randperm(10037, 1000);
Selected = M(k, :);
r = true(1,10037);
r(k) = false;
Remaining = M(r, :);
Richard Willey
il 7 Ott 2011
Statistics Toolbox includes a nice function called randsample
% Generate a matrix named foo
foo = randn(10000,2);
% draw 1000 random samples without replacement
index = randsample(1:length(foo), 1000);
bar = foo(index,:);
% draw 1000 random samples with replacement
index = randsample(1:length(foo), 1000, true);
bar = foo(index,:);
2 Commenti
Peter Perkins
il 7 Ott 2011
If you happen to be using R2011b, and have access to the Statistics Toolbox, you can also use the new datasample function:
m = rand(10037,9);
mnew = datasample(m,1000);
This also allows you to sample with replacement, or with weights.
Vedere anche
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!