如何在matlab中随机选择合理的数据

Question

How can I select randomly and fairly some data from a dataset in matlab?

When we use the randperm function to select data, they are random and fair?

Answer 1

As you already suggested, selecting k uniformly random chosen rows out of n can be done with randperm , assuming you don't want duplication.

Example:

dataSet = rand(1000,4);
idx = randperm(size(dataSet,1),10)
dataSet(idx,:)

Answer 2

If you have the Statistics Toolbox, you can use randsample :

sample = randsample(data,k);

takes k values sampled uniformly at random, without replacement, from the values in the vector data . See above link for other options.

Equivalent code with randperm :

ind = randperm(numel(data));
sample = data(ind(1:k));

Yes, either of these approaches gives random samples, and yes, they are fair . I assume that by "fair" you mean "uniform": each entry of data is picked with the same probability.

Answer 3

anything that uses uniform distribution is "fair". because the output is supposed to be distributed randomly in an specific range. for example, rand function in matlab.