Wsrtjtyk

I am newbie in R. I got a problem when combining data, hope that someone help to resolve it.
Suppose that I have two CSV files such as A.csv and B.csv are located at the path "C:UsersPublicA".
They look like that:

A.csv

T,2015,2016,2017,2018
X1,1,2,3,2
X2,1,2,2,3
X3,1,3,4,2

B.csv

T,2015,2016,2017
X1,2,4,3
X2,2,2,3
X3,3,3,4

And then I try to combine them as well as transpose them with following functions. They are created by Ricardo Oliveros-Ramos at here and by Tony Cookson at here.
1. Firstly, I create function read.tcsv to read and transpose data in CSV file

  read.tcsv = function(file, header=TRUE, sep=",", ...) {

  n = max(count.fields(file, sep=sep), na.rm=TRUE)

  x = readLines(file)



  .splitvar = function(x, sep, n) {

    var = unlist(strsplit(x, split=sep))

    length(var) = n

    return(var)

  }



  x = do.call(cbind, lapply(x, .splitvar, sep=sep, n=n))

  x = apply(x, 1, paste, collapse=sep) 

  out = read.csv(text=x, sep=sep, header=header, ...)

  return(out)



}

2. Then I use multrbind.fill to combine and fill missing value

multrbind.fill = function(mypath){

  filenames=list.files(path=mypath, full.names=TRUE)

  datalist = lapply(filenames, function(x){

    read.tcsv(file=x,header=T)

  }

)

    Reduce(function(x,y) {plyr::rbind.fill(x,y)}, datalist)

}

3. The result looks good:

ï..T X1 X2 X3
2015 1 1 1
2016 2 2 3
2017 3 2 4
2018 2 3 2
2015 2 2 3
2016 4 2 3
2017 3 3 4

4. However, I want to add a column as an identifier for each file with their file name (or unique IDs) like that:

ï..T ID X1 X2 X3
2015 A 1 1 1
2016 A 2 2 3
2017 A 3 2 4
2018 A 2 3 2
2015 B 2 2 3
2016 B 4 2 3
2017 B 3 3 4

Someone help me!? Thanks in advance.

Thanks TJ83 for helping me to correct the function. Base on TJ83's comments, I add an identifier column named ID. And here is my complete function read.tcsv

read.tcsv = function(file, header=TRUE, sep=",", ...) {

  n = max(count.fields(file, sep=sep), na.rm=TRUE)

  x = readLines(file)



  .splitvar = function(x, sep, n) {

    var = unlist(strsplit(x, split=sep))

    length(var) = n

    return(var)

  }



  x = do.call(cbind, lapply(x, .splitvar, sep=sep, n=n))

  x = apply(x, 1, paste, collapse=sep)



out = read.csv(text=x, sep=sep, header=header, ...)

out$ID<-tools::file_path_sans_ext(basename(file))

return(out)



} 

1) If you only have 2 datasets, then the fastest way would be to add an ID-column on A and B datasets after transformation but before binding the rows.

Dataset_A$ID<-"A"

Dataset_B$ID<-"B"

# Where Dataset_X is the name of your imported transformed datasets.

2) Could you show your exact code used? If you only have 2 datasets I think the code you have created could be simplified substantially. If you are interested in a simplification then please supply us with output from the 2 dput-statements below:

A<-read.csv("A-dataset")

B<-read.csv("B-dataset")

dput(A)

dput(B)