merging several dataframes from a list

library(zoo)
mylist.z <- lapply(mylist, function(x) zoo(x$data, as.character(x$pos)))
do.call(merge.zoo, mylist.z)

Henrique Dallazuanna schrieb:

Try this also:

 cbind(pos = mylist$df1$pos, data.frame(mylist)[grep("data",
names(data.frame(mylist)))])

Hi Henrique,

cool solution - that's seems to be the easiest way!
though I thought there should be some possibiliy of multiple merge

Anyway, this will do it for now!

Thank you!

On Wed, Jan 21, 2009 at 6:19 AM, Antje <niederlein-rstat at yahoo.de
<mailto:niederlein-rstat at yahoo.de>> wrote:

   Hi there,

   I have a list of dataframes (generated by reading multiple files)
   and all dataframes are comparable in dimension and column names.
   They also have a common column, which, I'd like to use for merging.
   To give a simple example of what I have:

   df1 <- data.frame(c(LETTERS[1:5]), c(2,6,3,1,9))
   names(df1) <- c("pos", "data")
   df3 <- df2 <- df1
   df2$data <- c(6,2,9,7,5)
   df3$data <- c(9,3,6,2,1)
   mylist <- list(df1,df2,df3)
   names(mylist) <- c("df1","df2","df3")

    > mylist

   $df1
    pos data
   1   A    2
   2   B    6
   3   C    3
   4   D    1
   5   E    9

   $df2
    pos data
   1   A    6
   2   B    2
   3   C    9
   4   D    7
   5   E    5

   $df3
    pos data
   1   A    9
   2   B    3
   3   C    6
   4   D    2
   5   E    1

   If I use do.call("cbind"), I'll end up with something like this

     pos data pos data pos data
   1   A    2   A    6   A    9
   2   B    6   B    2   B    3
   3   C    3   C    9   C    6
   4   D    1   D    7   D    2
   5   E    9   E    5   E    1


   but now, I don't know anymore which data comes from which
   dataframe... and I have the column "pos" multiple times...

   Instead I'd like to have it like this:

     pos df1 df2 df3
   1   A    2   6   9
   2   B    6   2   3
   3   C    3   9   6
   4   D    1   7   2
   5   E    9   5   1

   How, can I realize it? (The list, I'm working with has not just 3
   data frames like given in my example, so I need to automize it)


   Antje