[R] File conca.

[PIKAL Petr]

Hi

Help with such operations is rather tricky as only you know exact structrure
of your folders.

see some hints in line

> -----Original Message-----
> From: R-help <r-help-bounces using r-project.org> On Behalf Of Val
> Sent: Tuesday, November 5, 2019 4:33 AM
> To: r-help using R-project.org (r-help using r-project.org) <r-help using r-project.org>
> Subject: [R] File conca.
> 
> Hi All,
> 
> I have data files in several folders and want combine all  these files in
one
> file.  In each folder  there are several files  and these
> files have the same structure but different names.   First, in each
> folder  I want to concatenate(rbind) all files in to one file. While I am
> reading each files and concatenating (rbind) all files, I want to added
the
> folder name as one variable  in each row. I am reading the folder names
> from a file and for demonstration I am using only two folders  as shown
> below.
> Data\week1             # folder name 1
>            WT13.csv
>            WT26.csv           ...
>            WT10.csv
> Data\week2            #folder name 2
>            WT02.csv
>            WT12.csv
> 
> Below please find  my attempt,
> 
> folders=c("week1","week2")
> for(i in folders){
>   path=paste("\data\"", i , sep = "")
>   setwd(path)

you should use 
wd <- setwd(path)

which keeps the original directory for subsequent use

>   Flist = list.files(path,pattern = "^WT")
>   dataA =  lapply(Flist, function(x)read.csv(x, header=T))
>   Alldata = do.call("rbind", dataA)     # combine all files
>   Alldata$foldername=i                  # adding the folder name
> 

now you can do

setwd(wd)

to return to original directory
}

> The above works for  for one folder but how can I do it for more than one
> folders?

You also need to decide if you want all data from all folders in one object
called Alldata or if you want several Alldata objects, one for each folder.

In second case you could use list structure for Alldata. In the first case
you could store data from each folder in some temporary object and use rbind
directly.

something like

temp <- do.call("rbind", dataA)
temp$foldername <- i

Alldata <- temp
in the first cycle
and
Alldata <- rbind(Alldata, temp)
in second and all others.

Or you could initiate first Alldata manually and use only
Alldata <- rbind(Alldata, temp)

in your loop.

Cheers
Petr

> 
> Thank you in advance,
> 
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