How to put a delay on a loop in Ruby?

Question

For example, if I want to make a timer, how do I make a delay in the loop so it counts in seconds and do not just loop through it in a millisecond?

Answer 1

The 'comment' above is your answer, given the very simple direct question you have asked:

1.upto(5) do |n|
  puts n
  sleep 1 # second
end

It may be that you want to run a method periodically, without blocking the rest of your code. In this case, you want to use a Thread (and possibly create a mutex to ensure that two pieces of code are not attempting to modify the same data structure at the same time):

require 'thread'

items = []
one_at_a_time = Mutex.new

# Show the values every 5 seconds
Thread.new do
  loop do
    one_at_a_time.synchronize do
      puts "Items are now: #{items.inspect}"
      sleep 5
    end
  end
end

1000.times do
  one_at_a_time.synchronize do
    new_items = fetch_items_from_web
    a.concat( new_items )
  end
end