问题
I have given list of numbers,
x=[x1, x2, x3, x4, x5, x6];
non_zero=find(x);
I want Matlab to randomly select anyone among elements of 'non_zero' at a time. I searched online but there is no such function available to provide my required results.
回答1:
You could use the function randi to randomly select an integer from the set of valid indices.
x=[x1, x2, x3, x4, x5, x6];
non_zero=find(x);
index = randi(numel(non_zero));
number = x(non_zero(index))
Or, perhaps a bit more clear, first make a copy of x, remove the zero elements from this copy, and then select a random integer from the range [1 numel(x_nz)].
x=[x1, x2, x3, x4, x5, x6];
x_nz = x;
x_nz(x == 0) = 0;
index = randi(numel(x_nz));
number = x_nz(index)
To ensure that you do not get the same sequence each time, first call rng('shuffle') to set the seed for random number generation.
回答2:
Have you considered randsample or datasample?
x = [1 4 3 2 6 5];
randsample(x,1,'true') % samples one element from x randomly
randsample(x,2,'true') % two samples
datasample(x,1)
% Dealing with the nonzero condition
y = [1 2 3 0 0 7 4 5];
k = 2; % number of samples
randsample(y(y>0),k,'true')
datasample(y(y>0),k)
After posting this answer, I found this excellent answer from @Rashid (linked by @ChrisLuengo). He also suggests considering if datasample(unique(y(y>0),k) is appropriate.
来源：https://stackoverflow.com/questions/54844548/randomly-number-selector-from-a-given-list-of-numbers