Skip to content

Naming files within R code

5 messages · Nick Wray, Andrew Simmons, Ebert,Timothy Aaron +2 more

Nick Wray
# 
Hello    I have data from various Scottish river catchments in the form of
csv files.  I want to be able to download the files in turn and refer to
each one by an assigned name from a vector of names, but within R.  So, for
example, if my vector of names is c("tay","forth","don") I want to tell R
to refer to the sequences of dataframes as a variable name, ie the table
uploaded from the first csv becomes the object tay *within* R and so on, so
that I could the do things like write print(tay[,1]) etc,rather than having
to refer to a list eg print(riverlist[[1]][,1])  I don't know whether this
is possible but if it is I'd be grateful for any pointers
Thanks, Nick Wray
Andrew Simmons
# 
It's definitely possible to create R objects without knowing their names
using 'assign', but this is considered bad practice. For example,
assign("tay", riverlist[["tay"]])
And you could put that in a for loop, looping through the names of your
files.

You could consider using 'attach'. You would write something like
attach(riverlist) and it would assign your variables into a new environment
and put it on your search list. Only problem is that modifying these
objects will (generally) create new objects, and not modify the originals.
For example, tay[[1]] <- NA
will create a new variable tay in your global environment, and not modify
the variable in your
riverlist environment. Maybe that's how you want it to work, up to you.

In general though, I would say that making variables in either of these
manners is setting yourself up for failure. It is much better to do
tay <- read.csv(...)
forth <- read.csv(...)
...

One final solution is to do what you're currently doing, but use names to
refer to a data frame in a list, instead of integers.
For example, if your csv files are "tay.csv", "forth.csv", and "don.csv",
and you had those strings stored in a variable 'riverfiles'
then remove the .csv and give the riverlist some names like
names(riverlist) <- sub("[.]csv$", "", riverfiles)
I hope this helps.
On Sun, Mar 20, 2022, 18:03 Nick Wray <nickmwray at gmail.com> wrote:

            

      
      
      
    

        

      
      
    

        

  
  


  


      

    

    

      
      

        


  

        

      Ebert,Timothy Aaron
    

    

      
      #
    

  


  

      
Unless you want to make some transformation like tay/don it might work better to make a new variable with catchment and append one dataset to the other. If later you decide that was a bad choice, use pivot_wider to reorganize the data.
Tim

-----Original Message-----
From: R-help <r-help-bounces at r-project.org> On Behalf Of Nick Wray
Sent: Sunday, March 20, 2022 6:03 PM
To: r-help at r-project.org
Subject: [R] Naming files within R code

[External Email]

Hello    I have data from various Scottish river catchments in the form of
csv files.  I want to be able to download the files in turn and refer to each one by an assigned name from a vector of names, but within R.  So, for example, if my vector of names is c("tay","forth","don") I want to tell R to refer to the sequences of dataframes as a variable name, ie the table uploaded from the first csv becomes the object tay *within* R and so on, so that I could the do things like write print(tay[,1]) etc,rather than having to refer to a list eg print(riverlist[[1]][,1])  I don't know whether this is possible but if it is I'd be grateful for any pointers Thanks, Nick Wray


______________________________________________
R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see https://urldefense.proofpoint.com/v2/url?u=https-3A__stat.ethz.ch_mailman_listinfo_r-2Dhelp&d=DwICAg&c=sJ6xIWYx-zLMB3EPkvcnVg&r=9PEhQh2kVeAsRzsn7AkP-g&m=e3PR6lu4RXxbI3pz4G9YTtjhx4hngiq8Ri1ZGN8Zh1BnxmLp96ohrDR_XciLNAR5&s=h6PbgaQbzT184NTXJtdTDvmyk_W8ryszwocFp1o_yyA&e=
PLEASE do read the posting guide https://urldefense.proofpoint.com/v2/url?u=http-3A__www.R-2Dproject.org_posting-2Dguide.html&d=DwICAg&c=sJ6xIWYx-zLMB3EPkvcnVg&r=9PEhQh2kVeAsRzsn7AkP-g&m=e3PR6lu4RXxbI3pz4G9YTtjhx4hngiq8Ri1ZGN8Zh1BnxmLp96ohrDR_XciLNAR5&s=sLKcHu2BJ_iU2JW3WjaWFLlLYQaIQMTMvlwYWwRjm9M&e=
and provide commented, minimal, self-contained, reproducible code.

  
  


  


      

    

    

      
      

        


  

        

      Rui Barradas
    

    

      
      #
    

  


  

      
Hello,

You can read in the files in a `lapply` loop, assign the result to a 
list, say df_list, and

names(df_list) <- c("tay","forth","don")
list2env(df_list, envir = globalenv())


This creates 3 data.frames with those names in the global environment.

Hope this helps,

Rui Barradas

?s 22:02 de 20/03/2022, Nick Wray escreveu:

            

      
      
      
    

        

      
      
    

  
  


  


      

    

    

      
      

        


  

        

      Eric Berger
    

    

      
      #
    

  


  

      
A different approach is to give names to the list elements and use a
shorter name for the list.
Then the code looks close to what you want without actually changing
its structure.

names(riverlist) <- c("tay","forth","don")
l <- riverlist
print(l$tay[,1])

HTH,
Eric

        
On Mon, Mar 21, 2022 at 12:53 AM Rui Barradas <ruipbarradas at sapo.pt> wrote: