Hello Berend, Thanks for your quick response.
I am aware of the names() function, but this is not the answer to my question, since it will not work within the foo function. Let me try to explain it again! (: I want to analyze several datasets in a similar fashion and stored all data as seperate list components in a (here: $var1, $var2, $var3). Each component of that list has a unique name and will be sent through the foo()-function using a for-loop. This foo() function would (in my case) generate several plots and output files where I would like to use the name of the component ($var1, $var2 or $var3) in the labels and output file names. I currently am unable to do so. As such, my end-goal would be that the foo function returns the name of the list components and not [1] "a[[i]]", as deparse(substitute(x)) does. The output of foo() needs to be: [1] "var1" [1] "var2" [1] "var3" But I'm also happy with [1] "a[[\"var1\"]] [1] "a[[\"var2\"]] [1] "a[[\"var3\"]] (or something similar) This leads to the question: how can I adjust my foo() so it gives me the output mentioned above? I hope that this clears things up. -- Stan -----Original Message----- From: Berend Hasselman [mailto:b...@xs4all.nl] Sent: 15 November 2012 11:27 To: Gaj Stan (BIGCAT) Cc: r-help@r-project.org Subject: Re: [R] Extracting list names within a looped function On 15-11-2012, at 11:14, Gaj Stan (BIGCAT) wrote: > Hello all, > > I have the following problem: > > 1) A list was defined as 'a' > > a <- list("var1"=c(100:1), "var2"=c(1:100), "var3"=rnorm(100)) > > 2) a function 'foo' was defined that extracts the variable name assigned to x > using the deparse(substitute()) functionality. This name will then be used > within the function to generate specific output files, etc. > > foo <- function(x) { > print( deparse(substitute(x)) ) > } > > However, I am currently interested in looping through all list variables and > extract the list variable name from within the function. The current loop > (see below) will result in > > for(i in 1:length(a)) { > foo(a[[i]]) > } > [1] "a[[i]]" > > which actually does what I expected of deparse(substitute(x)), but is not > what I wanted. I would like to end up with something like > > [1] "var1" > [1] "var2" > [1] "var3" > > or > > [1] "a[[\"var1\"]]" > [1] "a[[\"var2\"]]" > [1] "a[[\"var3\"]]" > > Keep in mind that x has to be a matrix, and not a list. This to keep the > function as general as possible. > > Does anyone have any idea on how to tackle this? Is deparse(substitute(x)) > here the best way to go? Are there alternatives? I'm not sure if I understand what you want but will this give you what you seem to want: names(a) Berend ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
