iterating over files in a directory with R

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Try  help("list.files"), help("file.info"), help("file"),  and
look in the "see also" section in each of those help files for
other functions which you may find useful for doing this.

-  tom blackwell  -  u michigan medical school  -  ann arbor  -

Hello,

I'm an R newbie and was wondering whether there are R commands for iterating over files in a directory.  Basically what I want to do is to iterate over many files and apply some R functions to each file seperately.

e.g. for (each file in a directory) do { some R calculation with the info in that file }

Could someone please give me a pointer to how (or if) this might be done with R - I haven't yet been able to find anything relevant in the manuals.  Or would I need to call each file with some language such as Java and then use R once I have the file name?

Thanks for your help,

femke
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?list.files

?"for"

Hadley

Hello, 

I'm an R newbie and was wondering whether there are R commands for iterating over files in a directory.  Basically what I want to do is to iterate over many files and apply some R functions to each file seperately.  

e.g. for (each file in a directory) do { some R calculation with the info in that file }

Could someone please give me a pointer to how (or if) this might be done with R - I haven't yet been able to find anything relevant in the manuals.  Or would I need to call each file with some language such as Java and then use R once I have the file name?

Thanks for your help,

femke
	[[alternative HTML version deleted]]

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Hello, 

I'm an R newbie and was wondering whether there are R commands for iterating over files in a directory.  Basically what I want to do is to iterate over many files and apply some R functions to each file seperately.  
The apply() and related functions do iteration over various things,
and list.files() and choose.files() select files (the latter
interactively on Windows).

So something like this might do what you want:

 lapply(list.files(), function(x) paste('filename is ',x))

Duncan Murdoch

Hello,

I'm an R newbie and was wondering whether there are R commands for
iterating over files in a directory.  Basically what I want to do is to
iterate over many files and apply some R functions to each file
seperately.

e.g. for (each file in a directory) do { some R calculation with the
info in that file }

sapply(list.files("a directory"), some.R.calculation)

or

files<-list.files("a directory")
for(each.file in files){
	some.R.calculation
}

	-thomas
I usually do something like this:

filelist <- dir(path = ".") ## files in current directory

for(filename in filelist) {
	do.something(filename)
}

-roger

Hello, 

I'm an R newbie and was wondering whether there are R commands for iterating over files in a directory.  Basically what I want to do is to iterate over many files and apply some R functions to each file seperately.  

e.g. for (each file in a directory) do { some R calculation with the info in that file }

Could someone please give me a pointer to how (or if) this might be done with R - I haven't yet been able to find anything relevant in the manuals.  Or would I need to call each file with some language such as Java and then use R once I have the file name?

Thanks for your help,

femke
	[[alternative HTML version deleted]]

______________________________________________
R-help at stat.math.ethz.ch mailing list
https://www.stat.math.ethz.ch/mailman/listinfo/r-help
PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html