[R] initializing table and filling it out

[Gabor Grothendieck]

If you use lapply you don't have to set up the storage area.

Here is an example.  I have used textConnection with character
strings to make this reproducible but you can replace conn with
a vector of filenames,

# test data
Lines1 <- "
1 2
3 4
"

Lines2 <- "
11 12
13 14
"

conn <- list(textConnection(Lines1), textConnection(Lines2))

# this is code
f <- function(f) with(read.table(f), c(a = mean(V1), b = sd(V2)))
do.call(rbind, lapply(conn, f))



On 6/29/06, Cuau <cuauv at yahoo.com> wrote:
>
>   Hi everyone,
>
>     I'm writting a script that will open multiple files in a  single folder and then will do some calculations to finally save  everything in a big table.
>   So here  is the pseudo code
>
>  #read all files in the given directory
>  myfiles <-list.files("c:\\myDir")
>
>  #initialize table
>  ???
>
>  #loop through files
>  for(f in myfiles[-1]) {
>    netMat <- read.table( f, sep" " )
>    netMat <-as.matrix(netMat)
>
>   # calculate the needed Stats
>   gden(netMat)->density
>   centralization(netMat, degree) -> Gdegree
>   centralization(netMat, betweenness) -> Gbetweenness
>   centralization(netMat, closeness) -> Gcloseness
>
>  #store into table
>  ????
>
>  }
>
>    So my questions are two
>
>   First how can I initialize the table (it will be a 4 X 1001 table) without filling it out first.
>  Second how can I store each value in the table (i.e. in each round I'll  be adding one full column with density and the 3 different  centralizations)?
>
>  thks
>
>  -Cuau
>
>
>
>
> ---------------------------------
>
>
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