Help with vectors in MATLAB

[john2009]

Hi,

I need some help with vectors in Matlab.

I have a vector A with 100 elements. From previous calculations, 80 of the elements are 1 and the rest are zero.
But I need to make the vector with half of its element "zero" and the remaining half "one" by randomly turning some of the one's to zero.

So I need to turn 30 (out of 80 currently in the vector) 1's into zero and I have to do it randomly. Can anyone help me with this problem?

Thanks,
John.

 

[electricpete]

homework?

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[MikeyP]

N_init = 80;
N_reqd = 50;
idxrand = randperm(N_init);
idx1 = find(A);
A(idx1(idxrand(1:N_init-N_reqd))) = zeros(1,N_init-N_reqd);

M

--
Dr Michael F Platten