How can I determine the number of days between two Time instances in Ruby?
> earlyTime = Time.at(123)
> laterTime = Time.now
> time_difference = laterTime - earlyTime
I'd like to determine the number of days in time_difference (I'm not worried about fractions of days. Rounding up or down is fine).
Difference of two times is in seconds. Divide it by number of seconds in 24 hours.
(t1 - t2).to_i / (24 * 60 * 60)
require 'date'
days_between = (Date.parse(laterTime.to_s) - Date.parse(earlyTime.to_s)).round
Edit ...or more simply...
require 'date'
(laterTime.to_date - earlyTime.to_date).round
earlyTime = Time.at(123)
laterTime = Time.now
time_difference = laterTime - earlyTime
time_difference_in_days = time_difference / 1.day # just divide by 1.day
[1] pry(main)> earlyTime = Time.at(123)
=> 1970-01-01 01:02:03 +0100
[2] pry(main)> laterTime = Time.now
=> 2014-04-15 11:13:40 +0200
[3] pry(main)> (laterTime.to_date - earlyTime.to_date).to_i
=> 16175
To account for DST (Daylight Saving Time), you'd have to count it by the days. Note that this assumes less than a day is counted as 1 (rounded up):
num = 0
cur = start_time
while cur < end_time
num += 1
cur = cur.advance(:days => 1)
end
return num
Here is a simple answer that works across DST:
numDays = ((laterTime - earlyTime)/(24.0*60*60)).round
60*60 is the number of seconds in an hour
24.0 is the number of hours in a day. It's a float because some days are a little more than 24 hours, some are less. So when we divide by the number of seconds in a day we still have a float, and round will round to the closest integer.
So if we go across DST, either way, we'll still round to the closest day. Even if you're in some weird timezone that changes more than an hour for DST.
in_days (Rails 6.1+)
Rails 6.1 introduces new ActiveSupport::Duration conversion methods like in_seconds, in_minutes, in_hours, in_days, in_weeks, in_months, and in_years.
As a result, now, your problem can be solved as:
date_1 = Time.parse('2020-10-18 00:00:00 UTC')
date_2 = Time.parse('2020-08-13 03:35:38 UTC')
(date_2 - date_1).seconds.in_days.to_i.abs
# => 65
Here is a link to the corresponding PR.
None of these answers will actually work if you don't want to estimate and you want to take into account daylight savings time.
For instance 10 AM on Wednesday before the fall change of clocks and 10 AM the Wednesday afterwards, the time between them would be 1 week and 1 hour. During the spring it would be 1 week minus 1 hour.
In order to get the accurate time you can use the following code
def self.days_between_two_dates later_time, early_time
days_between = (later_time.to_date-early_time.to_date).to_f
later_time_time_of_day_in_seconds = later_time.hour*3600+later_time.min*60+later_time.sec
earlier_time_time_of_day_in_seconds = early_time.hour*3600+early_time.min*60+early_time.sec
days_between + (later_time_time_of_day_in_seconds - early_time_time_of_day_in_seconds)/1.0.day
end
Related
In my project i get from external system date&time in VARIANT DATE type and need to convert it to datetime (i.e. 43347.6625 => 04/09/2018 16:29:59).
Do you know how to do it in ruby? what is the best approach? I did not find any ruby built-in method to do such a conversion...
here a method to do the calculation, the date you give is not correct, it should be what this method is returning, check with https://planetcalc.com/7027/
def variant2datetime variant
# number of days after 1-1-1900 minus 2 days for starting with 0
# and having a day that didn't exist because 1900 wasn't a leap year
date = Time.new("1900-01-01") + (variant.to_i - 2) * 24 * 60 * 60
fraction = variant % 1
hours = (fraction - fraction.to_i) * 24
minutes = (hours - hours.to_i) * 60
seconds = (minutes - minutes.to_i) * 60
Time.new(date.year, date.month, date.day, hours.to_i, minutes.to_i, seconds.to_i)
end
variant2datetime 43347.6625 # 2018-09-04 15:53:59 +0200
How do I get the seconds from the day to Thursday 10:00 at that week? If later than Thursday 10:00, I want to get zero. For example:
seconds = (Thursday 10:00) - Time.now
Use Chronic:
require 'chronic'
Chronic.parse('this Thursday at 10:00 am') - Time.now
#=> 98688.251918432
You can subtract two time to get difference in seconds (see docs):
require 'time'
Time.parse(end_time) - Time.parse(time)
# => 57600.0
Update
To calculate difference between two time getting two fixed time is an absolute must. You can get time for next week simply by adding numeric time difference in seconds to existing time. Here:
next_week_time = Time.parse(end_time) + (1*7*24*60*60)
Or if you are on Rails, with ActiveSupport you can simply do:
next_week_time = Time.parse(end_time) + 1.weeks
(4-Time.now.wday-1)*24*3600: get the number of days from the day morning to Thursday of the week.
Time.now.seconds_until_end_of_day: get the rest seconds of the day.
seconds = (4-Time.now.wday-1)*24*3600 + Time.now.seconds_until_end_of_day + 10*3600
seconds = seconds > 0 ? seconds : 0
I want to check if Time.now is between two times (start, end) values which are stored as String in a two columns with the "%I:%M:%S" format.
I get the same format if I use Time.now.strftime("%I:%M:%S") ... but then I'm lost.
Try something like:
n = Time.now
t1 = Time.parse('1:30:4')
t2 = Time.parse('3:30:4')
n.to_f > t1.to_f and n.to_f < t2.to_f
I solved it, by using "time without time zone" in the columns "start" and "end" format.
Also, to check if the Time.now is between the values stored in the database I use Time.zone.now.
start < Time.zone.now
and end > Time.zone.now
You can convert the time to seconds since midnight and compare integers.
require 'date'
range_start = 79200 # 10pm (22 * 60 * 60)
range_end = 82800 # 11pm (23 * 60 * 60)
time_since_midnight = Time.now.to_i - Date.today.to_time.to_i
#Check if the the time now is between 10pm and 11pm
print time_since_midnight.between?(range_start, range_end)
There is the following task: I need to get minutes between one time and another one: for example, between "8:15" and "7:45". I have the following code:
(Time.parse("8:15") - Time.parse("7:45")).minute
But I get result as "108000.0 seconds".
How can I fix it?
The result you get back is a float of the number of seconds not a Time object. So to get the number of minutes and seconds between the two times:
require 'time'
t1 = Time.parse("8:15")
t2 = Time.parse("7:45")
total_seconds = (t1 - t2) # => 1800.0
minutes = (total_seconds / 60).floor # => 30
seconds = total_seconds.to_i % 60 # => 0
puts "difference is #{minutes} minute(s) and #{seconds} second(s)"
Using floor and modulus (%) allows you to split up the minutes and seconds so it's more human readable, rather than having '6.57 minutes'
You can avoid weird time parsing gotchas (Daylight Saving, running the code around midnight) by simply doing some math on the hours and minutes instead of parsing them into Time objects. Something along these lines (I'd verify the math with tests):
one = "8:15"
two = "7:45"
h1, m1 = one.split(":").map(&:to_i)
h2, m2 = two.split(":").map(&:to_i)
puts (h1 - h2) * 60 + m1 - m2
If you do want to take Daylight Saving into account (e.g. you sometimes want an extra hour added or subtracted depending on today's date) then you will need to involve Time, of course.
Time subtraction returns the value in seconds. So divide by 60 to get the answer in minutes:
=> (Time.parse("8:15") - Time.parse("7:45")) / 60
#> 30.0
I try to get a decimal amount of months for a date range. Example:
ruby-1.9.2-p0 > from = Date.new(2011, 7, 6)
=> Wed, 06 Jul 2011
ruby-1.9.2-p0 > to = Date.new(2011, 8, 31)
=> Wed, 31 Aug 2011
ruby-1.9.2-p0 > to - from
=> (56/1)
So the difference is 56 days. But I want and need the amount of months: 1.83
I have created the following piece of code which returns the correct result but doesn't feel like the ruby way:
months = Hash.new
(from..to).each do |date|
unless months.key? date.beginning_of_month
months[date.beginning_of_month] = 1
else
months[date.beginning_of_month] += 1
end
end
multiplicator = 0.0
months.each do |month, days|
multiplicator += days.to_f/month.end_of_month.day
end
return multiplicator.floor_to(2)
To be honest: It looks ugly and really inefficient. But I just cannot figure out any easier way.
Can you help me to find a better solution?
For further questions feel free to ask me.
Many thanks in advance!
Update/Solution: Solved the problem with the following piece of code:
months = 0.0
months += ((date_to < date_from.end_of_month ? date_to : date_from.end_of_month) - date_from + 1) / Time.days_in_month(date_from.month)
unless date_to.month == date_from.month
months += (date_to - date_to.beginning_of_month + 1) / Time.days_in_month(date_to.month)
months += date_to.month - date_from.month - 1
end
return months.floor_to(2)
a better way to do would be summation of
number of days left in from / number of days in from
number of days completed in to / number of days in to
number of months between from and to (from, to excluded)
This way you wont have iterations to do