如何在R中附加多个文件

Question

我正在尝试读取文件列表并将它们附加到包含所有记录的新文件中.我不打算改变原始文件中的任何内容.我尝试了几种方法.

方法1:此方法创建一个新文件,但在每次迭代时,再次添加先前的文件.因为我以递归方式绑定数据帧.

files <- list.files(pattern = "\\.csv$")

  #temparary data frame to load the contents on the current file
  temp_df <- data.frame(ModelName = character(), Object = character(),stringsAsFactors = F)

  #reading each file within the range and append them to create one file
  for (i in 1:length(files)){
    #read the file
    currentFile = read.csv(files[i])

    #Append the current file
    temp_df = rbind(temp_df, currentFile)    
  }

  #writing the appended file  
  write.csv(temp_df,"Models_appended.csv",row.names = F,quote = F)

方法2:我从Rbloggers获得了这个方法.此方法不会写入新文件,而是继续修改原始文件.

multmerge = function(){
  filenames= list.files(pattern = "\\.csv$")
  datalist = lapply(filenames, function(x){read.csv(file=x,header=T)})
  Reduce(function(x,y) {merge(x,y)}, temp_df)

}

有人可以就如何实现我的目标向我提出建议吗？

Answer 1

您可以使用它将所有内容加载到一个数据集中.

dataset <- do.call("rbind", lapply(file.list, FUN = function(file) {
  read.table(file, header=TRUE, sep="\t")
}))

然后只需保存write.csv.

Answer 2

它看起来像这样:

files <- list.files(pattern = "\\.csv$")

DF <-  read.csv(files[1])

#reading each file within the range and append them to create one file
for (f in files[-1]){
  df <- read.csv(f)      # read the file
  DF <- rbind(DF, df)    # append the current file
}
#writing the appended file  
write.csv(DF, "Models_appended.csv", row.names=FALSE, quote=FALSE)

或短:

files <- list.files(pattern = "\\.csv$")

DF <-  read.csv(files[1])
for (f in files[-1]) DF <- rbind(DF, read.csv(f))   
write.csv(DF, "Models_appended.csv", row.names=FALSE, quote=FALSE)

Answer 3

或者您可以继续在 R 中使用 shell 命令：

system2("cat", args = "*.csv", stdout = "appendedfiles.csv")

这适用于基于 UNIX 的系统；我不确定你会为 windows 做什么。