I have a list of files that I have called like so: main_dir <- '/path/to/files/' directories <- list.files(main_dir, pattern = '[[:alnum:]]', full.names=T)
filenames <- list.files(file.path(directories,"/tmpdir/"), pattern = '[[:alnum:][:punct:]]_eat.txt+$', recursive = TRUE, full.names=T) This lists around 35 Files. Each has multiple columns but they all have three columns in common: Burger, Stall and Cost which I want to merge on using: m1 <- Reduce(function(a, b) { merge(a, b, by=c("Burger",Stall","Cost")) }, filenames) However, I get the error: Error in fix.by(by.x, x) : 'by' must specify uniquely valid columns Is there something that I have obviously overlooked here? Thanks in advance! ______________________________________________ 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.