Ruby: Convert time to seconds?

user_147586 0
Viewed 36661

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 from midnight (00:00) to a specific time in the day (such as 10:30, or 18:45).

time ruby
8 Answers

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.

user_59584550

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
user_13183670
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