Issue:
overlaps? method doesn't return expect value.
(start_on.to_i..end_on.to_i).overlaps?(ti.start_time.to_i..ti.end_time.to_i)
It returns false, but should be true.
start_on: 2016-08-19 11:00:00 +0200
end_on: 2016-08-19 12:00:00 +0200
ti.start_time: 2000-01-01 08:00:00 UTC
ti.end_time: 2000-01-01 12:00:00 UTC
Hours like 11:00-12:00 overlaps with 08:00-12:00. Why method returns false? All columns in database are type of time. Current date is caused by Time.parse method.
I suppose that problem is with date second part of times have 2000 year, but first 2016. Anyone know how to fix it?
You can try by getting only time by this strftime("%H:%M").
Result:
(start_on.strftime("%H:%M")..end_on.strftime("%H:%M")).overlaps?(ti.start_time.strftime("%H:%M")..ti.end_time.strftime("%H:%M"))
Related
How should I interpret all aspects of the following timestamps? Where is the time based and how do timezones apply?
2015-11-15T14:45:28Z
2015-11-15T14:45:28.9694Z
2015-11-15T14:45:28.969412345Z
Below is my thoughts...
Date: 2015-11-15
???: T
Hours: 14
Minutes: 45
Seconds: 28 OR 28.9694 OR 28.969412345
???: Z
Most of your values are attributed correctly. The date portion (2015-11-15) is in the order YYYY-MM-DD, time in HH:MM:SS.ffff.
T indicates the start of the time portion of the date time.
Z indicates the time zone is UTC. Next to Z, you could have a format like Z+02:00, which indicates the time zone is UTC + 2 hours.
I've got a bunch of user-inputted dates and times like so:
date = "01:00pm 06/03/2015"
I'm trying to submit them to a datetime column in a database, and I'm trying to systemize them like this:
DateTime.strptime(date, '%m/%d/%Y %H:%M')
But I consistently get an invalid date error. What am I doing wrong? If I submit the string without strptime the record will save but it sometimes gets the date wrong.
Also, how can I append a timezone to a DateTime object?
Edit:
So .to_datetime and DateTime.parse(date) work for the date string and fail for date2. What's going on?
date2 = "03:30pm 05/28/2015"
Try using to_datetime:
date.to_datetime
# => Fri, 06 Mar 2015 13:00:00 +0000
Also if you read the documentation for DateTime#strptime, here. It states:
Parses the given representation of date and time with the given
template, and creates a date object.
Its important to note that the template sequence must match to that of input string sequence, which don't in your case - leading to error.
Update
Using to_datetime over second example will generate
ArgumentError: invalid date
This is because it expects the date to be in dd-mm-yy format. Same error will be raised for DateTime.parse as to_datetime is nothing but an api for the later. You should use strptime in-case of non-standard custom date formats. Here:
date2 = "03:30pm 05/28/2015"
DateTime.strptime(date2, "%I:%M%p %m/%d/%Y")
# => Thu, 28 May 2015 15:30:00 +0000
date = "01:00pm 06/03/2015"
DateTime.parse(date)
=> Fri, 06 Mar 2015 13:00:00 +0000
You haven't got your parameters in the correct order.
DateTime.strptime(date, '%H:%M%p %m/%d/%Y')
You'll also need to add %p for the am/pm suffix
controller action:
#days = (#date_start - Date.today)
rendering <%= #days %> returns
2/1
The first digit is correct. How is the rest being generated and what does it mean?
According to docs:
d - other → date or rational
Returns the difference between the two dates if the other is a date object. If the other is a numeric value, returns a date object pointing other days before self. If the other is flonum, assumes its precision is at most nanosecond.
So your (2/1) is a Rational number. You can check it with #days.class.
If your #date_start is also Date object - you can convert #days to Integer to get difference in days with #days.to_i without information loss since difference between Dates will always be (n/1)
But in general, method returns Rational, because you can also subtract DateTime objects(specifying not only date, but also time), like this:
DateTime.new(2001,2,3) - DateTime.new(2001,2,2,12)
# 03 Feb 2001 00:00:00 - 02 Feb 2001 12:00:00
# => (1/2)
And in this case only half of the day is between 03 Feb 2001 00:00:00 and 02 Feb 2001 12:00:00, thus it returns (1/2).
I am capturing the current time like so:
Time.now
My server runs on UTC. How can I convert the time to EST without using any Rails libraries? I am guessing some sort of offset but not sure how it works per say.
In plain Ruby you may use Time.zone_offset method:
require 'time'
t = Time.now # 2014-07-30 18:30:00 UTC
t + Time.zone_offset('EST') # 2014-07-30 13:30:00 UTC
The fbonetti's answer leads to the proper UTC to Eastern time conversion while accepted David Unric's answer would give wrong time for 8 months in 2017 (while DST is in effect).
Let's look at the following example:
First we'll need to figure out when DST starts/ends in 2017:
As we can see on March 12th, 2017 deep in the night (2:00am) they change time by adding +1 hour, so they "jump" from 1:59:59am up to 3:00:00am instantaneously! Which means there can not be 2:30am on March 12th, 2017.
Let's choose two UTC timestamps - one before and one after that switch, then we will try to convert those two timestamps from UTC back to Eastern.
First timestamp will be safely far enough from the switch moment:
require 'time'
t1 = Time.parse("2017-03-11 15:00:00 +0000")
=> 2017-03-11 15:00:00 +0000
t1_epoch_s = t1.to_i
=> 1489244400
Second timestamp is just +24 hours from the first one:
t2 = Time.parse("2017-03-12 15:00:00 +0000")
=> 2017-03-12 15:00:00 +0000
t2_epoch_s = t2.to_i
=> 1489330800
Now let us convert t1_epoch_s and t2_epoch_s to Eastern:
method-1: by adding Time.zone_offset('EST')
wrong, gives bad result: 10am for both days :(
and offset portion is shown as "+0000" which is also misleading and would refer to completely wrong point in time for people reading our output : ((
Time.at(t1_epoch_s) + Time.zone_offset('EST')
=> 2017-03-11 10:00:00 +0000
Time.at(t2_epoch_s) + Time.zone_offset('EST')
=> 2017-03-12 10:00:00 +0000
method-2: by changing timezone
Good!! Correctly yields 10am and 11am on next day!-)
ENV['TZ'] = 'America/New_York'
Time.at(t1_epoch_s)
=> 2017-03-11 10:00:00 -0500
Time.at(t2_epoch_s)
=> 2017-03-12 11:00:00 -0400
# resetting timezone back
ENV['TZ'] = nil
Basically manually adding Time.zone_offset('EST') is like adding constant and it will give right result for about 4 months (of 12 total) during the year, but then other time you'd have to manually add Time.zone_offset('EDT'), which is another constant. It pretty much same as "a broken clock is right twice a day": )) nasty!
And just for laughter let's see the "slow mo" how proper method handles the actual +1 hour magic jump in time:
ENV['TZ'] = "America/New_York"
Time.at(1489301999 + 0)
=> 2017-03-12 01:59:59 -0500
Time.at(1489301999 + 1)
=> 2017-03-12 03:00:00 -0400
ENV['TZ'] = nil
magic-magic!
In plain ruby, the timezone is determined by the 'TZ' environment variable. You could do something like this:
ENV['TZ'] = 'America/New_York' # set the TZ to Eastern Daylight Time
time = Time.now
time.zone
# => "EDT"
# do stuff
ENV['TZ'] = nil # reset the TZ back to UTC
If you don't mind using a gem,
require 'tzinfo'
tz = TZInfo::Timezone.get('US/Eastern')
Time.now.getlocal(tz.current_period.offset.utc_total_offset)
Credit: https://stackoverflow.com/a/42702906/2441263
I have an AWS server that runs daily cron jobs reporting on our user base. I want to ensure my report is run for the full day the previous day in MST. Currently I use this as the code for the data quering
Time.new(Time.now.year, Time.now.month, Time.now.day).yesterday.beginning_of_day.in_time_zone('MST)..Time.new(Time.now.year, Time.now.month, Time.now.day).yesterday.end_of_day.in_time_zone('MST)
I read it is bad practice to use Time.now as that is the system (UTC) time? I am wondering if what I am doing is a big no no or if there is a more efficient way?
thank you!
Mountain Standard Time is 7 hours behind UTC, so when you capture all the data points from the day of July 22rd in MST, you want the UTC times to be from 7/22 at 7:00AM UTC to 7/23 at 7:00AM UTC.
I don't think your code is correct because you are calling in_time_zone("MST") after beginning_of_day.
When you run this code on a server that is on UTC, the evaluated times are different:
>> Time.new.yesterday.beginning_of_day.in_time_zone('MST').utc
=> 2013-07-22 00:00:00 UTC
>> Time.new.in_time_zone("MST").yesterday.beginning_of_day.utc
=> 2013-07-22 07:00:00 UTC
Here is how you can determine the start and end times properly:
>> t = Time.new
=> 2013-07-23 19:45:10 +0000
>> start_time = t.in_time_zone("MST").yesterday.beginning_of_day
=> Mon, 22 Jul 2013 00:00:00 MST -07:00
>> end_time = t.in_time_zone("MST").yesterday.end_of_day
=> Mon, 22 Jul 2013 23:59:59 MST -07:00
When we convert the start and end times to UTC, we get the desired result.
>> start_time = t.in_time_zone("MST").yesterday.beginning_of_day.utc
=> 2013-07-22 07:00:00 UTC
>> end_time = t.in_time_zone("MST").yesterday.end_of_day.utc
=> 2013-07-23 06:59:59 UTC
I don't know what you are trying to do, but
Time.new(Time.now.year, Time.now.month, Time.now.day)
is definitely a terrible code fragment. For example, if the time lag between the execution time of Time.now.year and that of Time.now.month overlaps the moment of the change of the year, then the time object created with the main Time.new will be neither of the two moments. If you want to get the current time, just do
Time.new
or
Time.now
If you are trying to create a time range calculated out of a single time, then whatever your code should be, create time only once:
t = Time.now
and use that in the rest of your code:
t.some_method..t.some_other_method