如何从R中的矩阵中重复选择行样本? [英] How do I select a sample of rows at random with repetition from a matrix in R?

问题描述

如何从R的矩阵中随机选择重复的行样本?

How do I select a sample of rows at random with repetition from a matrix in R?

所以请清楚，我将从一个100行的矩阵开始，然后我可以从其中的5行中选择一个新的矩阵.我希望选择是否进行替换或不进行替换.

So do be clear, I would start with a matrix of, for example, 100 rows and I would be able to select 5 of those rows and make a new matrix. I would want the option of doing this either with or without replacement.

推荐答案

在具有replace=TRUE或replace=FALSE的行上使用sample.

如果X是您的原始矩阵，则

If X is your original matrix then

X[sample(nrow(X),size=5,replace=TRUE),]

或

X[sample(nrow(X),size=5,replace=FALSE),]

应该工作. (如果先选择示例:s <- sample(...)然后选择子集:newmat <- X[s,]，则可能更易读)

should work. (It may be more readable if you choose the sample first: s <- sample(...) and then subset: newmat <- X[s,])

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