R help - Dec 2010 - Counting number of datasets and appending them

Hi there,

I have a question on how to  read a bunch of dataset, assign each of the dataset
to a matrix in the  memory, and append them.

Suppose I have 20 dataset saved to different .rda files named gradeFileData1,
gradeFileData2,...., gradeFileData20. And I would like to read them each into a
dataset in the memory, then combine them. I wrote something like:

e1<-new.env(parent=.GlobalEnv)
maxi <- 20
i <- 1
while (i<=maxi) {
e1$d <-1
datanam <- paste("data",i,sep="")
data <- e1$d
names(data)[length(data)] <- datanam
i <- i+1
}

The function "names(data)[length(data)]" doesn't seem to work. I
need it to be named like data1,data2,,,,,data20.....

Also to append them into a big dataset, I think there should be something
simpler than
all <- rbind(data1,data2,data3,data4,data5,data6,data7,data8.........data20)

can you help me on this? I hope this is not some simplest R question..... I am a
beginner.

Thanks a ton!

Grace


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Hi Grace,

Try something along the lines of

do.call(rbind, lapply(1:maxi, function(x) get(paste('data', x, sep =
""))))

HTH,
Jorge


On Wed, Dec 29, 2010 at 5:06 PM, Li, Grace <> wrote:
> Hi there,
>
> I have a question on how to  read a bunch of dataset, assign each of the
> dataset to a matrix in the  memory, and append them.
>
> Suppose I have 20 dataset saved to different .rda files named
> gradeFileData1, gradeFileData2,...., gradeFileData20. And I would like to
> read them each into a dataset in the memory, then combine them. I wrote
> something like:
>
> e1<-new.env(parent=.GlobalEnv)
> maxi <- 20
> i <- 1
> while (i<=maxi) {
> e1$d <-1
> datanam <- paste("data",i,sep="")
> data <- e1$d
> names(data)[length(data)] <- datanam
> i <- i+1
> }
>
> The function "names(data)[length(data)]" doesn't seem to
work. I need it to
> be named like data1,data2,,,,,data20.....
>
> Also to append them into a big dataset, I think there should be something
> simpler than
> all <-
> rbind(data1,data2,data3,data4,data5,data6,data7,data8.........data20)
>
> can you help me on this? I hope this is not some simplest R question..... I
> am a beginner.
>
> Thanks a ton!
>
> Grace
>
>
> Confidentiality Notice: This e-mail message including at...{{dropped:12}}
>
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