R 对向量的每个元素中的单词重新排序

我想更改向量中每个元素的词序。具体地说，我想做另一个向量，其中第一个单词现在是许多长度不同的元素的最后一个单词

数据

metadata1 <- c("reference1 an organism", 
               "reference2 another organism here",
               "reference3 yet another organism is here")

---

metadata1感谢您快速准确的响应！我选择了
stringer:：word（）
解决方案，因为它允许我更轻松地将元数据与数据重新对齐。一种标准方法：
sub（“^（\\w+）（.*）”，“\\2\\1”，metadata1）
@Frank这也是一个出色的解决方案！
metadata2 <- c("an organism reference1", 
               "another organism here reference2",
               "yet another organism is here reference3")

metadata2 <- lapply(strsplit(metadata1," "), function(x) paste(x[c(2,3,4,5,1)]))

library(stringr)
paste(word(metadata1,2, -1), word(metadata1,1), sep = " ")
# [1] "an organism reference1"                 
# [2] "another organism here reference2"       
# [3] "yet another organism is here reference3"

# OR

sapply(metadata1, function(x){ y = unlist(strsplit(x, " "))
                           paste(c(y[-1],y[1]),collapse = " ")
                           })


# OR ( this is purely @Frank's answer)( Shall remove when he puts it as an answer)
sub("^(\\w+) (.*)$", "\\2 \\1", metadata1)