[R] 'For each file in folder F do....'

2005-11-27 Thread Ron Piccinini 
Hello,

I have 2700 text files in a folder and need to apply
the same program/procedure to each individually. I'm
trying to find how to code something like:

For each file in Folder do {Procedure}

is there an easy way to do this? other suggestions? 

I have tried to list all the files names in a vector
e.g.

listfiles[1:10,1] 

1   H:/Rtest/AXP.txt
2H:/Rtest/BA.txt
3 H:/Rtest/C.txt
4   H:/Rtest/CAT.txt
5H:/Rtest/DD.txt
6   H:/Rtest/DIS.txt
7H:/Rtest/EK.txt
8H:/Rtest/GE.txt
9H:/Rtest/GM.txt
10   H:/Rtest/HD.txt

but R doesn't like statements of type

read.table(file=listfiles[1,1])

since 'file' must be a character string or
connection...

Any thoughts?

Many thanks in advance,

Ron Piccinini.

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

Re: [R] 'For each file in folder F do....'

2005-11-27 Thread Kjetil Brinchmann Halvorsen 
Ron Piccinini wrote:
 Hello,
 
 I have 2700 text files in a folder and need to apply
 the same program/procedure to each individually. I'm
 trying to find how to code something like:
 
 For each file in Folder do {Procedure}
 
 is there an easy way to do this? other suggestions? 

files - listfiles()
results - lapply(files, yourprocessing())

where yourprocessing is a function taking as argument a file name and 
returning whatever you want.

Kjetil


 
 I have tried to list all the files names in a vector
 e.g.
 
 listfiles[1:10,1] 
 
 1   H:/Rtest/AXP.txt
 2H:/Rtest/BA.txt
 3 H:/Rtest/C.txt
 4   H:/Rtest/CAT.txt
 5H:/Rtest/DD.txt
 6   H:/Rtest/DIS.txt
 7H:/Rtest/EK.txt
 8H:/Rtest/GE.txt
 9H:/Rtest/GM.txt
 10   H:/Rtest/HD.txt
 
 but R doesn't like statements of type
 
 read.table(file=listfiles[1,1])
 
 since 'file' must be a character string or
 connection...
 
 Any thoughts?
 
 Many thanks in advance,
 
 Ron Piccinini.
 
 __
 R-help@stat.math.ethz.ch mailing list
 https://stat.ethz.ch/mailman/listinfo/r-help
 PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html


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

Re: [R] 'For each file in folder F do....'

2005-11-27 Thread Duncan Murdoch 
On 11/27/2005 3:51 PM, Ron Piccinini wrote:
 Hello,
 
 I have 2700 text files in a folder and need to apply
 the same program/procedure to each individually. I'm
 trying to find how to code something like:
 
 For each file in Folder do {Procedure}
 
 is there an easy way to do this? other suggestions? 
 
 I have tried to list all the files names in a vector
 e.g.
 
 
listfiles[1:10,1] 
 
 
 1   H:/Rtest/AXP.txt
 2H:/Rtest/BA.txt
 3 H:/Rtest/C.txt
 4   H:/Rtest/CAT.txt
 5H:/Rtest/DD.txt
 6   H:/Rtest/DIS.txt
 7H:/Rtest/EK.txt
 8H:/Rtest/GE.txt
 9H:/Rtest/GM.txt
 10   H:/Rtest/HD.txt
 
 but R doesn't like statements of type
 
 
read.table(file=listfiles[1,1])
 
 
 since 'file' must be a character string or
 connection...
 
 Any thoughts?

 From the look of it, the listfiles column that you created has been 
converted to a factor.  You can convert back to character using 
as.character(); the as.is=TRUE parameter in the file reading functions 
will prevent the conversion in the first place, if that's how it happened.

Then something like

results - list()
for (f in as.character(listfiles[,1])) results[[f]] - read.table(file=f)

will read all the files and put them in a list.

Duncan Murdoch

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