r - 将字符串粘贴到向量的每个其他元素上

Question

我有一个这样的向量:

test <- c("a","b","c","d")
test
[1] "a" "b" "c" "d"

我想粘贴一个字符串，例如“_2”，到向量的每个其他元素上，得到这个:

"a" "b_2" "c" "d_2"

我试过这个命令:

ifelse(test %in% seq(1, length(test), 2), test, paste(test, "_2", sep=""))

但这只是给了我:

"a_2" "b_2" "c_2" "d_2"

这是错误的。关于如何正确执行此操作的任何建议？谢谢!

Answer 1

怎么样

paste0(c("a","b","c","d"), c("", "_2"))

[1] "a"   "b_2" "c"   "d_2"