How can you sort an array in Ruby starting at a specific letter, say letter f?

Question

I have a text array.

text_array = ["bob", "alice", "dave", "carol", "frank", "eve", "jordan", "isaac", "harry", "george"]

text_array = text_array.sort would give us a sorted array.

However, I want a sorted array with f as the first letter for our order, and e as the last.

So the end result should be...

text_array = ["frank", "george", "harry", "isaac", "jordan", "alice", "bob", "carol", "dave", "eve"]

What would be the best way to accomplish this?

Answer 1

Try this:

result = (text_array.select{ |v| v =~ /^[f-z]/ }.sort + text_array.select{ |v| v =~ /^[a-e]/ }.sort).flatten

It's not the prettiest but it will get the job done.

Edit per comment. Making a more general piece of code:

before = []
after = []
text_array.sort.each do |t|
  if t > term
    after << t
  else
    before << t
  end
end
return (after + before).flatten

This code assumes that term is whatever you want to divide the array. And if an array value equals term, it will be at the end.