如何生成向量的所有可能组合 [英] How can I generate all the possible combinations of a vector

问题描述

我有一个向量，比如 A,B,C,D,E，我有兴趣生成向量元素的所有可能组合.下面给出了所需的输出.

I have a vector, say A,B,C,D,E and I am interested in generating all the possible combination of the vector elements. The desired output is given below.

BA,CA,DA,EA,CB,DB、EB、DC、EC、ED

推荐答案

尝试

combn(v1, 2, FUN=function(x) paste(rev(x), collapse="-"))
#[1] "B-A" "C-A" "D-A" "E-A" "C-B" "D-B" "E-B" "D-C" "E-C" "E-D"

如果你想按默认顺序

combn(v1, 2, FUN=paste, collapse="-")
#[1] "A-B" "A-C" "A-D" "A-E" "B-C" "B-D" "B-E" "C-D" "C-E" "D-E"

更新

为了更快的选择，您可以使用 grBase 中的 combnPrim.检查此处

Update

For a faster option, you can use combnPrim from grBase. Check here

library(grBase) 
apply(combnPrim(v1,2), 2, FUN=paste, collapse='-')
#[1] "A-B" "A-C" "B-C" "A-D" "B-D" "C-D" "A-E" "B-E" "C-E" "D-E"

数据

v1 <- LETTERS[1:5]

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