随机m×n矩阵的randperm子集 [英] randperm subset of random m-by-n matrix

问题描述

您如何使用randperm选择一个m×n的数据矩阵并输出该随机数据的较小子集?

how do you use randperm to select a m-by-n matrix of data and output a smaller subset of that random data?

即

newfile = randperm(data(m = 2000, n = 3));  %% save random m-by-n data as newfile

推荐答案

请考虑以下示例:

data = rand(8,6);
m = 4;
n = 2;

%# pick random rows
indX = randperm( size(data,1) );
indX = indX(1:m);

%# pick random columns
indY = randperm( size(data,2) );
indY = indY(1:n);

%# filter data
data2 = data(indX,indY)

请注意，R2011b为 RANDPERM 引入了更简单的语法，使您可以直接编写:

Note that R2011b introduced an easier syntax for RANDPERM, allowing you to directly write:

indX = randperm(size(data,1), m);
indY = randperm(size(data,2), n);

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