列表中的每个元素都对应一个向量。我想将向量中的所有元素更改为指定值。例如：

x <- c("x1","x2","x3")
y <- list(1:5,1:10,1:15)
Ans <- list()
for (i in 1:length(y)){
  Ans[[i]] <- rep(x[i],length(y[[i]]))  
}

结果是：

[[1]]
[1] "x1" "x1" "x1" "x1" "x1"

[[2]]
 [1] "x2" "x2" "x2" "x2" "x2" "x2" "x2" "x2" "x2" "x2"

[[3]]
 [1] "x3" "x3" "x3" "x3" "x3" "x3" "x3" "x3" "x3" "x3" "x3" "x3" "x3" "x3" "x3"

R中是否有可以处理此问题的函数？