Hi

I would like to write a script that reads a list of variable names. These variable names are some of the column headers in a data.frame. Then I want do a for-loop to execute various operations on the specified variables in the data.frame, but can't figure out how to do the necessary variable substitution. In bash (or C) I would use "$var", but there seems to be no equivalent in R. The data.frame has 300 columns and 2500 rows. Not all columns are continuous variables, some are factors, descriptors, etc., so I use the varlist to pick which columns I want to analyze.

#Example script
varlist<-read.table(/path/to/varlist)
for (i in 1:length(varlist)){
	res<-mean(Dataset$SOMETHINGHERE_i )
	write(res) somewhere
}

Something like that. Any suggestions?

Thanks

Jon

Soli Deo Gloria

Jon Erik Ween, MD, MS
Scientist, Kunin-Lunenfeld Applied Research Unit 
Director, Stroke Clinic, Brain Health Clinic, Baycrest Centre
Assistant Professor, Dept. of Medicine, Div. of Neurology
    University of Toronto Faculty of Medicine

Kimel Family Building, 6th Floor, Room 644 
Baycrest Centre
3560 Bathurst Street 
Toronto, Ontario M6A 2E1
Canada 

Phone: 416-785-2500 x3648
Fax: 416-785-2484
Email: jween@klaru-baycrest.on.ca


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