从列表列表开始，比如outcome：

id <- c(1,2,3,4,5,1,2,3,4,5)
month <- c(3,4,2,1,5,7,3,1,8,9)
preds <- c(0.5,0.1,0.15,0.23,0.75,0.6,0.49,0.81,0.37,0.14)

l_1 <- data.frame(id, preds, month)

preds <- c(0.45,0.18,0.35,0.63,0.25,0.63,0.29,0.11,0.17,0.24)

l_2 <- data.frame(id, preds, month)

preds <- c(0.58,0.13,0.55,0.13,0.76,0.3,0.29,0.81,0.27,0.04)

l_3 <- data.frame(id, preds, month)

preds <- c(0.3,0.61,0.18,0.29,0.85,0.76,0.56,0.91,0.48,0.91)

l_4 <- data.frame(id, preds, month)

outcome <- list(l_1, l_2, l_3, l_4)

我的兴趣是获取分配的唯一行值并创建一个新变量，就像我们这样做一样：

sample <- outcome[[1]]
sample$unique_id <- rownames(sample)

然而，我不想手动操作，因为我的列表有100个列表。此外，我不想手动为每行赋值，因为我想保留R生成的行名称。如何才能做到这一点？