Question

SITE ADMIN: WOULD YOU PLEASE REMOVE THIS POST?

For example, I have

tt = [0, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0]

and I would like to slim it down to

tt_out = [0, 1, 1, 2, 2, 1, 1, 0, 0]

also I’d like to know when does the repetition begins and ends, hence I’d like to have the following tip

tip = '0','1.','.5','6.','.11','12.','.15','16.','.20'

Answer 1

tt = [0, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 0, 0, 0, 0, 0]
tip = []
tt_out = tt.map.with_index{|t, i|
  start_range = (i==0 || tt[i-1] != tt[i])
  end_range = (tt[i+1] != tt[i])
  if start_range && end_range
    tip << "#{i}"
  elsif start_range
    tip << "#{i}."
  elsif end_range
    tip << ".#{i}"
  end
  t if start_range || end_range
}.compact

tip
=> ["0", "1.", ".5", "6.", ".11", "12.", ".15", "16.", ".20"]
tt_out
=> [0, 1, 1, 2, 2, 1, 1, 0, 0]

P.S: You’ve got an error in your example, the last element of tip should be ‘.20’