Update variable while reading in files in R loop

Question

I am reading multiple txt files and I would like to remove the first row and save it as a variable, transpose it and later when I'm done doing stuff I would like to save it along with other variables in a file.

The problem is that my code is just saving the first txt information and repeating it for the rest of the txt files.

My code:

    for(i in 1:length(filesW))
{
  data <- read.table(paste0("data",i,".txt", sep=""), sep=",", header=TRUE)
  winstepsdat2 <- data.frame(data)


  genparameter<-t((winstepsdat2[1,]))
  winstepsdat<-winstepsdat2[-1,]

  num_col<-ncol(winstepsdat)
  num_row<-nrow(winstepsdat)

  colnames(winstepsdat) <- paste("i", 1:num_col, sep="")
  winstepsdat$name<- paste ("p", 1:num_row, sep="")

  #must change ni and labels for 1:n??
  cmd <- wcmd(title = "R2Winsteps Example", data=paste0("data",i,".txt"),item1 = 1, ni =num_col , name1 = 30, namelen = 20,labels = paste('i',                                                                                                                                1:num_col, sep = ""), hlines = "Y" ) #codes=1:5

  write.wdat(winstepsdat, cmd)

  write.wcmd(cmd, paste0("CMFILE[",i,"].cmd"))

  winsteps2(cmd, outfile=paste0("outfile[",i,"].txt"), pfile=paste0("pfile",i,".txt"), ifile=paste0("ifile",i,".txt"), windir="C:/Winsteps/Winsteps.exe")

} #end for

Somehow winstepsdat does change as I go through text files (given that I get different values for other calculations, but genparameter just keeps the first txt file values. How can I store/save genparameter for every text file I read?

I'm a beginner programmer so I would appreciate the help. Thanks, Shmy

Eudald · Accepted Answer · 2017-12-27 21:33:14Z

1

I don't know if I understand your question correctly, but I am guessing that what you need is to initialize the variables (for instance, as lists), and then fill the list with the for loop.

Something like:

genparameter = list()
winstepsdat = list()
for(i in 1:length(filesW)) #i don't know what the length(filesW) was doing here
{
 data <- read.table(paste0("data",i,".txt", sep=""), sep=",", header=TRUE)
winstepsdat2 <- data.frame(data)

genparameter[[i]]<-t((winstepsdat2[1,])
winstepsdat[[i]] <-winstepsdat2[-1,]

...

answered Dec 27, 2017 at 21:33

Eudald

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7 Comments

Gregor Thomas Over a year ago

I don't think this is what OP is trying to do, but I do think it's what OP should do :)

Shmy Over a year ago

@Eudald, thank you but sadly it didn't work. When I read the first text file the values do not get updated as the loop continues through the next text file. length (filesW) goes through my files that's how long I want the loop to me :)

Eudald Over a year ago

Mmmm, I see... Can you give me the whole function and what you expect it to do? Then I might understand better what the problem is.

Shmy Over a year ago

@Eudald, Yes, I updated my post with the whole code (because the comment section warned me I had too many characters). Basically, I don't know why the loop doesn't go beyond the first text file. Thank you for trying!

Eudald Over a year ago

What is filesW? Have you checked that its length exists and it's bigger than 1? (I know it sounds stupid but these kind of things often happen to me...)

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