How can I convert row names in multiple data frames to column in data frame>

dataframe, r, r-rownames

Solution

Youve got a `dataframe` with columns named "w,x,y,z" . Just do

data$names <- rownames(data)

to add a new column.

edit

In response to Boogie's query, here's `lapply` with an anonymous function to do the loop.

   foo = as.data.frame(matrix(1:15,3,5))
    rownames(foo) <-c('frist','prime','lastly')
    foo
    bar = list(foo,t(foo), rbind(foo,foo))
    bar[[1]] = as.data.frame( foo)
    bar[[2]] =data.frame( t(foo))
    bar[[3]] = data.frame(rbind(foo,foo))
    bar
    bar = lapply(bar,FUN= function(x) { x$date <-rownames(x);return(x)})
    bar

Problem

I have a list of `.csv` files that I have read in to R and placed in a large data frame called `data` that consists of 6 data.frames which are the 6 files in `filenames`. My code so far is: ``` filenames <- list.files( paste(mainDirInput,sep=""), pattern="Out.*csv", full.names=TRUE) data = lapply(filenames, function(f) { wb = read.csv(f, header=TRUE) }) ``` The row names and column names in each data.frame are exactly the same, I would like to extract the row names and instead have them as the first column in R. An example of one of my data frames would be like this: ``` w x y z 2012 01 12 43 87 09 2012 02 14 53 75 76 2012 03 76 34 76 28 2012 04 41 36 85 16 : : : : : : : : : : ``` I need to be able to use this code on other files as well, so I can't simply just create a new column with the values `2012 01, 2012 02, 2012 03...`

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