diff --git a/R/laydi/R/laydi.R b/R/laydi/R/laydi.R
index 22d1fa3..b6fc85a 100644
--- a/R/laydi/R/laydi.R
+++ b/R/laydi/R/laydi.R
@@ -27,4 +27,19 @@ write.ftsv <- function(data, con, name="unnamed_dataset", rowdim="rows", coldim=
         close(con)
 }
 
+write.laydi.selection <- function(data, con) {
+    # If con is a file name, open it 
+    opened.here = FALSE
+    if (is.character(con)){
+        con = file(con, "w")
+        opened.here = TRUE 
+    }
+    
+    writeLines(gsub("\\s", "_", data), con=con)
+    
+    # If con was a string, close file now 
+    if (opened.here)
+        close(con)
+}
+
 
diff --git a/R/laydi/man/laydi-package.Rd b/R/laydi/man/laydi-package.Rd
index 5bb3515..8566157 100644
--- a/R/laydi/man/laydi-package.Rd
+++ b/R/laydi/man/laydi-package.Rd
@@ -18,6 +18,7 @@ LazyLoad: \tab yes\cr
 
 library(laydi)
 write.ftsv(matrix, file, ...)
+write.laydi.selection(idlist, file)
 
 }
 \author{
@@ -34,6 +35,4 @@ Maintainer: Einar Ryeng <einarr@pvv.org>
 % ~~ \code{\link[<pkg>:<pkg>-package]{<pkg>}} ~~
 }
 \examples{
-library(laydi)
-write.ftsv(randu, con="/tmp/randu.ftsv")
 }
diff --git a/R/laydi/man/write.laydi.selection.Rd b/R/laydi/man/write.laydi.selection.Rd
new file mode 100644
index 0000000..8558bed
--- /dev/null
+++ b/R/laydi/man/write.laydi.selection.Rd
@@ -0,0 +1,61 @@
+\name{write.laydi.selection}
+\alias{write.laydi.selection}
+\title{write.laydi.selection}
+\description{
+Writes a Laydi selection file from a list of identifiers. Identifiers are
+written one per line, with all whitespace characters substituted with
+underscores.
+}
+\usage{
+write.laydi.selection(data, con)
+}
+\arguments{
+  \item{data}{
+     A list of identifiers. All whitespace characters will be replaced wity
+     underscores in the output. (Laydi requires unique identifiers along a
+     dimension, and does not allow identifiers to contain spaces.) This method
+     does not ensure that identifiers are unique.  
+  }
+  \item{con}{
+     Connection (or file name) to write the data to. If con is a character
+     string, it will be treated as a file name, and a file by that name will be
+     created, written to and closed. If con is an open connection (file descriptor),
+     the file will remain open.
+  }
+}
+
+\details{
+%%  ~~ If necessary, more details than the description above ~~
+}
+\value{
+%%  ~Describe the value returned
+%%  If it is a LIST, use
+%%  \item{comp1 }{Description of 'comp1'}
+%%  \item{comp2 }{Description of 'comp2'}
+%% ...
+}
+\references{
+Laydi and the laydi R package are not published in the litterature. Source code
+can be found at http://dev.pvv.ntnu.no/projects/laydi
+}
+\author{
+Einar Ryeng
+}
+\note{
+%%  ~~further notes~~
+}
+
+%% ~Make other sections like Warning with \section{Warning }{....} ~
+
+\seealso{
+%% ~~objects to See Also as \code{\link{help}}, ~~~
+}
+\examples{
+
+write.laydi.selection(c("sample1", "sample2", "sample3", "/tmp/selected_samples"))
+
+}
+
+\keyword{ IO }
+\keyword{ file }
+