在R中创建嵌套序列

Question

我想创建以下vector两个嵌套sequences,加上字母a和b:

desired.data <- c('a1b1', 'a1b2', 'a1b3', 'a2b1','a2b2', 'a2b3', 
                  'a3b1', 'a3b2', 'a3b3', 'a4b1','a4b2', 'a4b3', 
                  'a5b1', 'a5b2', 'a5b3')

我怀疑这是重复的,但我搜索Stack Overflow了一个小时没有成功.谢谢你的任何建议.

Answer 1

使用paste0,rep其each参数,并依靠载体回收:

paste0("a", rep(1:5, each = 3), "b", 1:3)
#[1] "a1b1" "a1b2" "a1b3" "a2b1" "a2b2" "a2b3" "a3b1" "a3b2" "a3b3" "a4b1" "a4b2" "a4b3" "a5b1" "a5b2" "a5b3"

Answer 2

如果字符串中的模式比两个数字和两个字符更复杂，那么这是一种替代解决方案，该解决方案可能更可行

concat <- function(x) paste0('a', x[, 2], 'b', x[, 1])
concat(expand.grid(1:3, 1:5))
#[1] "a1b1" "a1b2" "a1b3" "a2b1" "a2b2" "a2b3" "a3b1" "a3b2" "a3b3" "a4b1" "a4b2" "a4b3" "a5b1" "a5b2" "a5b3"