R中带有for循环的多个数据帧上的行名

Question

我有几个数据框。我希望第一列是每一行的名称。

我可以这样处理 1 个数据帧：

# Rename the row according the value in the 1st column
row.names(df1) <- df1[,1]

# Remove the 1st column
df1 <- df1[,-1]

但我想在几个数据帧上这样做。我尝试了几种策略，包括分配和一些获取，但没有成功。这是我尝试过的两种主要方法：

# Getting a list of all my dataframes
my_df <- list.files(path="data")

# 1st strategy, adapting what works for 1 dataframe
for (i in 1:length(files_names)) {
  rownames(get(my_df[i])) <- get(my_df[[i]])[,1] # The problem seems to be in this line
  my_df[i] <- my_df[i][,-1]
}

# The error is  Could not find function 'get>-'

# 2nd strategy using assign()
for (i in 1:length(my_df)) {
  assign(rownames(get(my_df[[i]])), get(my_df[[i]])[,1]) # The problem seems to be in this line
  my_df[i] <- my_df[i][,-1]
}

# The error is : Error in assign(rownames(my_df[i]), get(my_df[[i]])[, 1]) : first argument incorrect

我真的看不出我错过了什么。当我输入get(my_df[i]) 和get(my_df[[i]])[,1] 时，它在控制台中单独运行...

非常感谢那些可以帮助我的人:)

Answer 1

我们可以使用lapply或purrr::map这样的循环函数来循环所有的data.frames，然后使用dplyr::column_to_rownames，这大大简化了过程。不需要显式的 for 循环。

library(purrr)
library(dplyr)

map(my_df, ~ .x %>% read.csv() %>% column_to_rownames(var = names(.)[1]))

Answer 2

您可以编写函数中的代码，读取数据并将每个数据帧传递给函数。

change_rownames <- function(df1) {
  row.names(df1) <- df1[,1]
  df1 <- df1[,-1]
  df1  
}

my_df <- list.files(path="data")

list_data <- lapply(my_df, function(x) change_rownames(read.csv(x)))