How to stack individual raster layers from files contained in individual subfolders in R?

问题

I am working with raster layers. I have 10 subfolders in a parent folder. Each of the subfolders contains hundreds of raster. I would like to apply a script for each of the subfolders and to create several stacks for each of my subfolders.

#List all my subfolders in my parent folder
list_dirs<- list.dirs(path/parentfolder/, recursive = F) 

for (i in list_dir){

# set the working directory to the subfolder i
setwd(i) 

# List all the files with a certain pattern in the subfolder i
s<- list.files(path=setwd(i), pattern = "cool", recursive=F)

# I do not see how I can create a stack for each of my subfolders here.
#I should have an index i somewhere in the last line.

ss<- stack(s)

}

As a final output, I would like to have 10 stacks corresponding to each of my 10 subfolders. I am new in R. Thanks!

回答1:

You should typically use lists for this kind of thing. You can add each stack as a list element in the loop.

stack.list <- list()
for (i in 1:length(list_dirs)){
  s <- list.files(path=list_dirs[i], pattern = "cool", recursive=F, full.names = TRUE)
  stack.list[[i]] <- stack(s)
  }

Or, slightly better if you want to keep track of which list element corresponds to which folder, you can use:

stack.list[[basename(list_dirs)[i]]] <- stack(s)

回答2:

A lapply option if you prefer, but really just a different version of dww's answer:

list_dirs <- list.dirs("path/parentfolder/", recursive = F)

names(list_dirs) <- basename(list_dirs)

raster.list <- lapply(list_dirs, function(dir) {
  stack(list.files(dir, pattern = "cool", full.names = T, recursive = F))
})

来源：https://stackoverflow.com/questions/50628255/how-to-stack-individual-raster-layers-from-files-contained-in-individual-subfold

标签

file

loops