在上面的示例中，我试图将regex字符串作为文件名输入read.delim，但read.delim无法接受
我能够使用下面的代码实现所需的输出。

setwd("path/to/directory/contining/files") # Define the folder where the raw data files are to be read from
root.dir <- getwd() # Assign that folder as the `root.dir` object

import_and_merge <- function(root.dir){
    
  files <- fs::dir_ls(root.dir, regexp = ".txt$") # loads all the .txt files in from the `root.dir` folder
  data <- files %>%  # Create a data frame called `data`
  
  purrr::map_dfr(read_delim, .id = "Sample") %>% # imports all the files identified above into the `data` data frame and adds a column which includes the .txt filename for each row of data imported
  
  mutate(Sample = str_extract(Sample, "([0-9]{4}-[0-9]{2}-[0-9]{2}_[0-9]{2}[a-z]{1}[0-9]{2}[a-z]{1}[0-9]{2})")) # extracts the date and time stamp from the full .txt file name row
  
  now <- parsedate::format_iso_8601(Sys.time()) #  Create object called `now`, which contains a specific date and time stamp, accurate to 1 second ins ISO8601 format

  filename <- paste0("merged-data_",now,".csv") # Define the name for the merged file to be written out

  out.dir <- "/path/to/directory/to/contain/outputs" # Define the folder where you want to merged file to be exported to. This should not be the same folder as the raw data

  write.csv(data, paste0(out.dir, filename), row.names = FALSE) # Export the merged data as a .csv file into the defined out folder.

}

### Now the function is loaded, I can run it as below ###

import_and_merge(root.dir) # Run this function with `root.dir`.