读取多个.rds文件并创建一个对象

Question

I have seen other examples of this on stackexchange but cannot seem to adapt them to my code.

Problem: I have a folder of .rds files that I would like to read into R, then stack all the files together so I can take the mean and standard deviation. All the .rds files are 'Formal class RasterLayer' when brought into R, if that is pertinent.

Example code:

 # file path to folder where .rds files are stored
   path = "~/Predictions/"
   # create place to store files
   stack <-""
   # create vector of all .rds files in folder
   pred.dates <- dir(path, pattern =".rds")
   # loop to bring in each .rds file
   for(i in 1:length(pred.dates)){
   file <- readRDS(file.names[i],".rds")
   stack <- rbind(stack, file)
   }

   # take mean of all .rds files stacked together and plot 
   pred_mean <- mean(stack, na.rm=T)
   plot(pred_mean)

   # take sd of all .rds files stacked together and plot 
   pred_sd <- sd(stack, na.rm = T)
   plot(pred_sd)

However, it returns the error:

Error in gzfile(file, "rb") : cannot open the connection
In addition: Warning message:
In gzfile(file, "rb") :
  cannot open compressed file 'Pred_.rds', probable reason 'No such file or directory'

Seems like this should be straightforward, but perhaps I'm not using the correct function. Thanks!

Answer 1

You can do:

files <- list.files(path = path, pattern = "\\.rds$", full.names = TRUE)
stack <- do.call("rbind", lapply(files, readRDS))

Answer 2

I think the problem with the solution by F. Privé is that they use rbind instead of stack . I would suggest doing

library(raster)
files <- list.files(path = path, pattern = "\\.rds$", full.names = TRUE)
r <- lapply(files, readRDS)
s <- stack(r)