使用匹配为数据帧列表创建新列

Question

我有一个要在其上执行lapply函数的数据帧列表。其目标是通过将行名与另一个引用数据帧进行匹配，将新列symbol添加到每个数据帧中。这在非lapply形式中非常有效：

df1$symbol <- dds$symbol[ match(rownames(df1), rownames(dds)) ]

但是通过多次语法尝试在lapply中失败。我得到的最接近的似乎是：

result_list <- c("df1", "df2", "df3")
lapply(result_list, function(x) {
  x$symbol <- dds$symbol[ match(rownames(x), rownames(dds)) ]
})

[[1]]
character(0)

[[2]]
character(0)

[[3]]
character(0)

Warning messages:
1: In x$symbol <- mcols(dds)$symbol[match(rownames(x), rownames(dds))] :
  Coercing LHS to a list
2: In x$symbol <- mcols(dds)$symbol[match(rownames(x), rownames(dds))] :
  Coercing LHS to a list
3: In x$symbol <- mcols(dds)$symbol[match(rownames(x), rownames(dds))] :
  Coercing LHS to a list

或者：

lapply(result_list, function(x) {
  x[["symbol"]] <- dds$symbol[ match(rownames(x), rownames(dds)) ]
})
Error in x[["symbol"]] <- dds$symbol[ match(rownames(x), rownames(dds)) ] :
  replacement has length zero

lapply(result_list, function(x) {
  x[["symbol"]] <- dds[["symbol"]][ match(rownames(x), rownames(dds)) ]
})
Error in x[["symbol"]] <- dds[["symbol"]][ match(rownames(x), rownames(dds)) ] :
  replacement has length zero

Answer 1

我们需要在一个列表中获取“字符串”的值。mget根据标识符以字符串的形式从返回'data.frame's

lst1 <- mget(result_list)

然后循环访问“lst1”

lapply(lst1, function(x) {
   x$symbol <- dds$symbol[ match(rownames(x), rownames(dds)) ]
   x
   })