## 2005-07-28

Categories: Blog post Tags: Data management R software

I regularly work from home on my laptop, and when I need to re-run some analyses in R, I usually just re-create the original data sets. But there are several ways you can transfer objects from one R system to another.

The dump function creates a text file with the R commands needed to re-create the objects.

> a <- sample(letters,10) > a [1] "y" "f" "r" "k" "t" "x" "u" "a" "q" "v" > b <- sample(1:100,10) > b [1] 51 78 68 13 55 76 90 32 30 43 > dump(c("a","b"),file="d:/Data/dump.txt")

Here's what the file looks like:

"a" <- c("y", "f", "r", "k", "t", "x", "u", "a", "q", "v") "b" <- as.integer(c(51, 78, 68, 13, 55, 76, 90, 32, 30, 43))

You could then use the source function in R to re-create the objects. Note that you have to put the object names in quotes. If I had said

dump(a,file="d:/Data/dump.txt")

the system would have looked for objects names y, f, etc. producing either an error, when the objects were not found or an unexpected list of objects.

The save command creates a binary file (typically, this uses the extension .Rdata). You can't look at a binary file to see what is inside, but a binary file allows more efficient and more accurate storage of the objects. You would use the load function or possibly the attach function in R to re-create the data.

To save everything, use the function

save(ls(all=TRUE),"d:/Data/complete.Rdata")

and then use

load("d:/Data/complete.Rdata")

to re-create the data.