Question

I’m trying to build an array of folders with the files contained in each. So if your directory structure is:

DirA
  |- FileA
  \- FileB
DirB
  \- FileC

And I’m given this array:

files = ["DirA/FileA", "DirA/FileB", "DirB/FileC"]

I’m trying to build a hash like this

{DirA => [FileA, FileB], DirB => [FileC]}

Right now I’m doing it in what I think is a fairly non-Rubyish way (assume String has a method defined which fetches the parent directory):

h = {}
files.each do |f|
    parent = f.getParentDir
    if not h[parent] then h[parent] = [] end
    h[parent].push f
end

Is there are more elegant way?

Answer 1

I would do

h = {}
files.each do |f|
    (h[f.getParentDir] ||= []) << f
end