each_slice ruby with a skip the first x slices

Question

I have a backup script, which I take all the objects in a directory, and then with each slice of 30,000 I back them up to S3. My questions is now that I have over 100,000 objects, I would like to skip to slice number 2 but I am unsure how to do that. So the beginning of the loop looks like -

directory.files.each_slice(30000) do |file_array|

directory.files.each_slice(30000).skip(1) 

Any thoughts?

Thanks!

Answer 1

each_slice returns an enumerable which you can then call further enumerable methods on, so you could use with_index to do something like

directory.files.each_slice(30000).with_index { | file_array, i | 
    next if i == 2 
    upload file_array 
}

Answer 2

Your hypothetical skip method is called drop:

directory.files.each_slice(30000).drop(1).each do |file_array|

Note that like all Enumerable methods, it is not type-preserving, it always returns an Array, even though you are calling it on an Enumerator. Since you only have about 4 slices at the moment, that's not going to be a problem, but if you had millions of slices, that would eat up your memory pretty quickly.

Answer 3

How about this:

directory.files.each_slice(30000).with_index do |files, idx| 
  next if idx == 0
  ...
end