Ruby: Convert time to seconds?

Question

How can I convert a time like 10:30 to seconds? Is there some sort of built in Ruby function to handle that?

Basically trying to figure out the number of seconds fro

Answer 1

Yet another implementation:

Time.now.to_i - Date.today.to_time.to_i # seconds since midnight

Answer 2

I like these answers very much, especially Teddy's for its tidyness.

There's one thing to note. Teddy's answer gives second of day in current region and I haven't been able to convert Date.today.to_time to UTC. I ended up with this workaround:

Time.now.to_i % 86400

It's based on the fact that Time.now.to_i gives seconds since Unix Epoch which is always 1970-01-01T00:00:00Z, regardless of your current time zone. And the fact that there's 86400 seconds in a day as well. So this solution will always give you seconds since last UTC midnight.

Answer 3

You can simply use

Time.parse("10:30").seconds_since_midnight

Answer 4

In plain ruby the fastest is the sum of time parts:

require 'benchmark'
require 'time'

Benchmark.bm do |x|
  x.report('date') { 100_000.times { Time.now.to_i - Date.today.to_time.to_i } }
  x.report('parse') { 100_000.times { Time.now.to_i - Time.parse('00:00').to_i } }
  x.report('sum') { 100_000.times { Time.now.hour * 3600 + Time.now.min * 60 + Time.now.sec } }
end

       user     system      total        real
date  0.820000   0.000000   0.820000 (  0.822578)
parse  1.510000   0.000000   1.510000 (  1.516117)
sum  0.270000   0.000000   0.270000 (  0.268540)

So, here is a method that takes timezone into account, if needed

def seconds_since_midnight(time: Time.now, utc: true)
  time = time.utc if utc
  time.hour * 3600 + time.min * 60 + time.sec
end

Answer 5

The built in time library extends the Time class to parse strings, so you could use that. They're ultimately represented as seconds since the UNIX epoch, so converting to integers and subtracting should get you what you want.

require 'time'
m = Time.parse('00:00')
t = Time.parse('10:30')

(t.to_i - m.to_i)
=> 37800

There's also some sugar in ActiveSupport to handle these types of things.

Answer 6

Perhaps there is a more succinct way, but:

t = Time.parse("18:35")
s = t.hour * 60 * 60 + t.min * 60 + t.sec

would do the trick.