Loading data from RData files into a single data table

Question

I'm trying to load data from data frame objects of all `.RData` files in a specified directory into a single data table. This is how I've tried to do this: ``` library(data.table) fileList <- list.files("../cache/FLOSSmole", pattern="\.RData$", full.names=TRUE) dataset <- rbindlist(lapply(fileList, FUN=function(file) {as.data.table(load(file))})) ``` However, the result is different from the expected (single data table containing all data) - it contains just names of data frame objects from the source `.RData` files: ``` > str(dataset) Classes ‘data.table’ and 'data.frame': 39 obs. of 1 variable: $ V1: chr "lpdOfficialBugTags" "lpdLicenses" "lpdMilestones" "lpdSeries" ... - attr(*, ".internal.selfref")= > head(dataset) V1 1: lpdOfficialBugTags 2: lpdLicenses 3: lpdMilestones 4: lpdSeries 5: lpdProjects 6: lpdProgrammingLanguages ``` What am I doing wrong? Your help is greatly appreciated! My R environment: ``` > sessionInfo() R version 3.1.0 (2014-04-10) Platform: x86_64…

Accepted Answer

`.RData` is a saved workspace, it may contain data frames, but it is not a data frame. How many data frames are there in each `.RData`? You can load multiple `.RData` files and they add to the current workspace. Just load them all then `merge` or `rbind` the data.frames once they are in your current workspace

```
# lapply(FileList,function(x) load(x)) # Changed to a for loop, I guess the lapply was only loading into the lapply environment which disappears when the function ends
for (i in 1:length(FileList)) {
   load(FileList[i])
}
my.list <- vector(length(ls()),mode="list")
for (i in 1:length(ls())) {
    my.list[[i]] <- get(ls()[i])
}
my.rbind <- do.call(rbind,my.list)
```

This is one way. An easier way would be to save individual tables as delimited text files in the first place.

Loading data from RData files into a single data table

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