Hi everybody
I have a large number of Excel speadsheets that I want to merge into one R
dataframe to process. I can read them one by one with read.xls but I really
need a function to read a whole directory at once and merge the columns with
the same name into a single dataframe.

here is what I have thus far (on Mac OS X 10.5.2. for R 2.8.0):

# Define the directory where the data is

path="/Users/home/mydata/"

# Make a list of the filenames (they are all .xls so no need for a regular
expression seekig out ones ending in .xls )

files=list.files(path="/Users/home/mydata/")

# Read them into a list called data

data=tapply(paste(path,files,sep=""),files[1:length(files)],read.xls)


This gives the data in a list. What I want is a dataframe. I can turn it
into a matrix with as.matrix() but that only has one column which is more or
less the same as a list.

I have tried to merge different parts of the list :

mdata=date.frame(merge(data[[1]],data[[2]]))

but that gives an empty data frame (with the correct variable names).


Even if it worked I need a way to do that with a large number of file (i.e.
not manualy).  I also tried to use lapply with merge as function but that
didn't work either


Does anyone have any ideas? I would much appreciate it


regards

Chrisitiaan

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