Following my previous posts on how to read/write Excel files from Matlab here is the way I use to read/write Excel files from R. Again it seems the Apache POI java library made developers’life easy. I use here the simple-yet-powerful xlsx package (documentation here in PDF; project website).

Here you don’t need to install any additional files, installing the xlsx package from R does all the dirty work that for you. Then, reading an Excel file is very easy:

libary(xlsx)
inData <- read.xlsx2("input.xls", sheetName="Contactmatrix", header=FALSE)

I usually use read.xlsx2 instead of read.xlsx. It is said to be faster with large matrices and I had the opportunity to experience it – so I stick with this. You can read xls, xlsx and xlsm files without issue (well, with the simple formatting I usually use).

Writing to an Excel file is also very easy:

write.xlsx2(outData, "output.xls", sheetName="Random2", col.names=FALSE, row.names=FALSE)

Easy, isn’t it?