如何从所有组合中有效地随机选择多个组合？ [英] How to randomly pick a number of combinations from all the combinations efficiently?

问题描述

我知道函数 combn 可以生成所有可能的组合。但是，如果成员总数很大，那确实是耗时和内存消耗。

I know function combn can generate all the possible combinations. However, if the total number of members is large, this is really time-consuming and memory-consuming.

我的目标是从所有可能的组合中随机选择组合。例如，我想要3000个成员池中的5000个不同的三元组成员。我想我不需要生成所有可能的组合并从中选择5000个。但是R似乎没有现成的功能来执行此操作。那么如何解决这个问题呢？

My goal is to randomly pick combinations from all the possible combinations. For example, I want 5000 distinct triple set of members from a pool of 3000 members. I think I don't need to generate all possible combinations and choose 5000 from them. But seems that R doesn't have a ready-to-use function to do this. So how to deal with this problem?

推荐答案

这并不是您真正需要的，但是也许可以使您入门： p>

This is not exactly what you need but perhaps it can get you started:

 library(data.table) #to make the table easier
 members=1:3000;
 X=data.table(RUN=1:5000)
 X<-X[,as.list(sample(members, 3)),by=RUN]

这将创建3个从成员向量中随机选择的新列。看到它们作为每个成员的ID。

This will create 3 new columns that are randomly selected from the members vector. See them as IDs of each member.

我将使用以下方法进行检查，以查看有多少唯一身份：

I would do a check to see how many as unique using:

 X[duplicated(X, by=c('V1','V2','V3'))]

这对您有帮助吗？

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