如何追加R中的多个文件 [英] How to append multiple files in R

问题描述

我试图读取文件的列表，并把它们添加到一个新的文件，所有记录即可。我不打算改变原始文件什么。我试过几个方法。

I'm trying to read a list of files and append them into a new file with all the records. I do not intend to change anything in the original files. I've tried couple of methods.

方法1：：此方法创建一个新的文件，但在每次迭代时previous文件被再次添加。因为我递归绑定的数据帧。

Method 1: This methods creates a new file but at each iteration the previous file gets added again. Because I'm binding the data frame recursively.

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：我接到的 Rbloggers 。这种方法不会写一个新的文件，但不断修改原始文件。

Method 2: I got this method from Rbloggers . This methods won't write to a new file but keeps on modifying the original file.

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)

}

有人能指点我如何实现我的目标？

Can someone advice me on how to achieve my goal?

推荐答案

这可能是这样的：

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)

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