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"