convert time DD:hh:mm:ss format into seconds in Rails 3

Question

I need to get time value of DD:hh:mm:ss into seconds. Value is an output from a postgresql db query and looks something like this:

db_value = '456:14:56:10'

and I need to get it into seconds, I have an method in my application which does vice versa like this:

def time_converter(seconds)
  days = seconds / 86400
  seconds -= days * 86400
  hours = seconds / 3600
  seconds -= hours * 3600         
  minutes = seconds / 60
  seconds -= minutes * 60
  return "#{days}:#{hours}:#{minutes}:#{seconds}"

Can I use this method somehow or is it possible to change format in postgresql into seconds? What is the most efficient way of doing it?

db value is part of a SUM((end_time - start_time)* multiplier) AS duration query.

Answer 1

You didn't state which version of ruby you were using, so I'm assuming something modern. This should work on 1.9.3 or later. This also assumes that you always have all 4 fields present. It should give you some ideas anyway.

> db_value = '456:14:56:10'
=> "456:14:56:10"
> units = %w{days hours minutes seconds}
=> ["days", "hours", "minutes", "seconds"]
> db_value.split(":").map.with_index{|x,i| x.to_i.send(units[i])}.reduce(:+).to_i
=> 39452170