Question

我想将列号添加到数据框中的列名称前面。这样做的最佳方法是什么？

例如，我想在下表中找到类似“1_mpg”，“2_cyl”的内容：

structure(list(mpg = c(21, 21), cyl = c(6, 6)), .Names = c("mpg", 
"cyl"), row.names = c("Mazda RX4", "Mazda RX4 Wag"), class = "data.frame")

然后如何将其扩展到数据框列表？

list(structure(list(mpg = c(21, 21), cyl = c(6, 6)), .Names = c("mpg", 
"cyl"), row.names = c("Mazda RX4", "Mazda RX4 Wag"), class = "data.frame"), 
structure(list(mpg = c(21, 21), cyl = c(6, 6)), .Names = c("mpg", 
"cyl"), row.names = c("Mazda RX4", "Mazda RX4 Wag"), class = "data.frame"))

Answer 1

这是我最终使用的（尽管我猜测有更优雅的东西）：

# sample list of 2 data frames
x =
  list(structure(list(mpg = c(21, 21), cyl = c(6, 6)), .Names = c("mpg", 
  "cyl"), row.names = c("Mazda RX4", "Mazda RX4 Wag"), class = "data.frame"), 
  structure(list(mpg = c(21, 21), cyl = c(6, 6)), .Names = c("mpg", 
  "cyl"), row.names = c("Mazda RX4", "Mazda RX4 Wag"), class = "data.frame"))

# create function to append an index to column names
newColNames = function(a) {
          b=lapply(seq_along(colnames(a)), 
          function(i) paste(i,"_",colnames(a)[i],sep=""))
          colnames(a)=b
          return(a)
          }

# apply function
new_list = lapply(x, function(y) newColNames(y))

将列索引添加到数据框列表中的列名称

1 个答案: