给定约束，生成所有组合

本文介绍了给定约束，生成所有组合的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

如何在4个块中生成2种处理（A，B）的6种组合的全部，从而在每个块中使用R来获得相等数量的A和B？

How can I generate all of the 6 combinations of 2 treatments (A,B) in blocks of 4, such that in each block there is an equal number of A's and B's, using R?

"AABB","ABAB","ABBA","BBAA","BABA","BAAB"

PS组合的数量计算如下：

P.S. The number of combinations is calculated as follows:

如果

T = #treatments n = #treatments in each block = k*T,

组合数等于 n！ / [k！* k！ （T次）]

谢谢

推荐答案

类似的事情应该起作用：

Something like this should work:

library(gtools) t <- c('A','B') k <- 2 n <- k * length(t) t2 <- rep(t, k) m <- permutations(n,n) res <- unique(apply(m,MARGIN=1,function(x) paste(t2[x],collapse=''))) -------------------------------------------------------------------- res [1] "ABAB" "ABBA" "AABB" "BAAB" "BABA" "BBAA"