How to append multiple files in R - r

Question

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.
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$")
#temparary data frame to load the contents on the current file
temp_df <- data.frame(ModelName = character(), Object = character(),stringsAsFactors = F)
#reading each file within the range and append them to create one file
for (i in 1:length(files)){
#read the file
currentFile = read.csv(files[i])
#Append the current file
temp_df = rbind(temp_df, currentFile)
}
#writing the appended file
write.csv(temp_df,"Models_appended.csv",row.names = F,quote = F)
Method 2: I got this method from Rbloggers . This methods won't write to a new file but keeps on modifying the original file.
multmerge = function(){
filenames= list.files(pattern = "\\.csv$")
datalist = lapply(filenames, function(x){read.csv(file=x,header=T)})
Reduce(function(x,y) {merge(x,y)}, temp_df)
}
Can someone advice me on how to achieve my goal?

Answer 1

it could look like this:
files <- list.files(pattern = "\\.csv$")
DF <- read.csv(files[1])
#reading each file within the range and append them to create one file
for (f in files[-1]){
df <- read.csv(f) # read the file
DF <- rbind(DF, df) # append the current file
}
#writing the appended file
write.csv(DF, "Models_appended.csv", row.names=FALSE, quote=FALSE)
or short:
files <- list.files(pattern = "\\.csv$")
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 2

You can use this to load everything into one data set.
dataset <- do.call("rbind", lapply(file.list, FUN = function(file) {
read.table(file, header=TRUE, sep="\t")
}))
And then just save with write.csv.

Answer 3

Or you could go ahead and use shell commands in R:
system2("cat", args = "*.csv", stdout = "appendedfiles.csv")
This would be for unix based systems; I'm not sure what you would do for windows.

Answer 4

Try this for your ListOfFileNames:
ListOfFileNames<-list.files(pattern=".txt")
outFile <- file("all.txt", "w")
for (i in ListOfFileNames){
x <- readLines(i)
writeLines(x, outFile) # in the link the 1st and last line are skipped
}
close(outFile)
Source: https://r.789695.n4.nabble.com/R-Read-multiple-text-files-and-combine-into-single-file-td817344.html

Answer 5

There's an easy answer with rbind_list() now!
For instance:
dataFiles = map(Sys.glob("*.csv"), read.csv)
or however you're reading the files into a list
dat = rbind_list(dataFiles)
and dat will be what you're looking for!

Answer 6

If using Windows, it's easy to do this using the command prompt.
Start -> Run -> type "cmd" and hit return key
cd <path to folder>
copy /b *.txt <outputname>.txt
Concrete example:
cd C:\User\danny\docs\folder_with_txt files
copy /b *.txt concatenated.txt
Note that if you're changing drive letters to do this before cd
D:\> c:
C:\> cd C:\User\danny\docs\folder_with_txt files
copy /b *.txt concatenated.txt