ActiveSupport::TimeZone.new(-4).parse("2012-08-20T14:00:00-0400")
returns
Mon, 20 Aug 2012 15:00:00 ADT -03:00
I would expect parse() to return a Time with -04:00, like Mon, 20 Aug 2012 14:00:00 EDT -04:00
How would you handle this? I think that Daylight Saving Time is messing up things here.
I've handled this problem using new_offset from DateTime.
time = "2012-08-20T14:00:00-0400"
DateTime.parse(time).new_offset("+2")
returns Mon, 20 Aug 2012 20:00:00 +0200
Related
I'm trying to parse this date Wed, 17 Feb 2021 13:00:00 +0100 into this 2021-02-17 13:00:00.000000000 +0100.
And I've tried using this Time.strptime(current_time.to_s, '%Q'), (where current_time it's the date above) but I get 1970-01-01 01:00:02.021 +0100
But I don't understand why I get another date, could you help me? Thanks!
I'm trying to parse this date Wed, 17 Feb 2021 13:00:00 +0100 [...]
You seem to already have an instance of Time: (or ActiveSupport::TimeWithZone which is Rails' drop-in replacement with better timezone support)
current_time = Time.current
#=> Thu, 19 May 2022 10:09:58.702560000 CEST +02:00
In this case, there's nothing to parse. You just have to format it via strftime the way you like:
current_time.strftime('%F %T.%N %z')
#=> "2022-05-19 10:09:58.702560000 +0200"
Parsing is only needed when you have a string representation that you want to turn into a Time object, e.g.: (using Rails' Time.zone.parse variant)
time_string = 'Thu, 19 May 2022 10:09:58.702560000 CEST +02:00'
time_obj = Time.zone.parse(time_string)
#=> Thu, 19 May 2022 10:09:58.702560000 CEST +02:00
time_obj.class
#=> ActiveSupport::TimeWithZone
Given a (UTC) DateTime object, how can I get the corresponding time in Berlin, in CET or CEST, depending on the date?
Examples for the desired "convert" function:
convert(DateTime.new(2018, 07))
=> Sun, 01 Jul 2018 02:00:00 +0200
convert(DateTime.new(2018, 12))
=> Sat, 01 Dec 2018 01:00:00 +0100
Try this
require 'tzinfo'
timezone = TZInfo::Timezone.get('Europe/Berlin')
local_time = timezone.utc_to_local(utc_time)
That even works without Rails.
I need to use .next_week not +1.week. Because the .next_week make the date next week and Monday at the same time. It's so comfortable. And then I subtract some hours. But nothing has been changed. Here's my code.
newDate = DateTime.now
newDate = newDate.next_week - 3.hours
=> Sun, 30 Aug 2015 21:00:00 +0900
newDate = newDate.next_week - 3.hours
=> Sun, 30 Aug 2015 21:00:00 +0900
newDate = newDate.next_week - 3.hours
=> Sun, 30 Aug 2015 21:00:00 +0900
Why they can't be used same time? Please explain to me. Thanks.
This has nothing to do with #next_week and - 3.hours working at the same time. It is a misunderstanding about how #next_week works.
#next_week assumes by default a week is Monday-Sunday. This means when calling just #next_week it will return the next Monday at 00:00:00:00.
Example:
DateTime.now.next_week
#=> Mon, 03 Aug 2015 00:00:00 -0400
Okay so that make sense. Now you are substracting 3.hours making it Sunday again
DateTime.now.next_week - 3.hours
#=> Sun, 02 Aug 2015 21:00:00 -0400
Still makes perfect sense. Now here is where the confusion is. Since you rolled back to Sunday by subtracting 3.hours the #next_week is the following Monday again so
(DateTime.now.next_week - 3.hours).next_week
#=> Mon, 03 Aug 2015 00:00:00 -0400
I hope this helps you understand the situation a bit better.
If you use + 1.week this will take you to the same exact point in time the following week
DateTime.now + 1.week
#=> Fri, 07 Aug 2015 09:01:17 -0400
This does not rely on a weekly calendar but rather the basic math of adding 7 days to the referenced Date object.
In conclusion while #next_week might be comfortable you need to understand what it actually implies and I think I would prefer + 1.week in this case for its flexibility and its lack of assumption.
There are also many other methods for traversing time through ActiveSupport such as #advance, #days_since, weeks_since, etc.
Final note next_week can accept a day parameter as well e.g
DateTime.now.next_week(:tuesday)
#=> Tue, 04 Aug 2015 00:00:00 -0400
DateTime.now.next_week(:thursday)
#=> Thu, 06 Aug 2015 00:00:00 -0400
I have a hash like this:
a = {:start=>"Tue, 27 Jan 2015 13:00:00 +0000", :end=>"Tue, 27 Jan 2015 13:30:00 +0000", :title=>"2015-01-27T13:00:00+00:00 to 2015-01-27T13:30:00+00:00"}
and another hash like
b = {:start=>Tue, 27 Jan 2015 13:30:00 +0000, :end=>Tue, 27 Jan 2015 14:00:00 +0000, :title=>"2015-01-27T13:30:00+00:00 to 2015-01-27T14:00:00+00:00"}
I want to merge these two into
c = {{:start=>"Tue, 27 Jan 2015 13:00:00 +0000", :end=>"Tue, 27 Jan 2015 13:30:00 +0000", :title=>"2015-01-27T13:00:00+00:00 to 2015-01-27T13:30:00+00:00"},{:start=>Tue, 27 Jan 2015 13:30:00 +0000, :end=>Tue, 27 Jan 2015 14:00:00 +0000, title=>"2015-01-27T13:30:00+00:00 to 2015-01-27T14:00:00+00:00"}}
I tried the following:
c = a.merge(b)
and also
a.merge!(b)
This gave back only one value and
c = a+b
gave errors.
How to do this?
Its syntactically incorrect even for JSON, I believe. You want an array of hashes, by turning the outer {} into []. Better: c = [a,b].to_json
So right now it is 2:54 PM PST in San Francisco. For some reason, this code block is not returning 12:54 PM HST in Hawaii. Am I missing something here? I would expect this code to return me the current time in Hawaii
Time.use_zone('Hawaii') do
Time.now
end
# => 2012-01-03 14:54:54 -0800
This should work ok:
Time.use_zone('Hawaii') do
p Time.zone.now
end
Try using Time.now.in_time_zone inside your block instead.
> Time.use_zone('Hawaii') do
> Time.now.in_time_zone
> end
=> Tue, 03 Jan 2012 13:07:06 HST -10:00
Use Time.current if you want now with timezone support. Time.now is dangerous when working in a timezone aware application, as a rule of thumb I never use Time.now, only Time.current. Rails time helpers like 2.hours.ago and 4.days.from_now are based off of Time.current as well.
# Time.current will use Time.zone when needed (when Time.zone is present)
def current
::Time.zone ? ::Time.zone.now : ::Time.now
end
Also, this is a great article with a great cheat sheet at the bottom: https://www.varvet.com/blog/working-with-time-zones-in-ruby-on-rails/
DOs
code
result
2.hours.ago
Thu, 27 Aug 2015 14:39:36 AFT +04:30
1.day.from_now
Fri, 28 Aug 2015 16:39:36 AFT +04:30
Time.zone.parse("2015-08-27T12:09:36Z")
Thu, 27 Aug 2015 16:39:36 AFT +04:30
Time.current
Thu, 27 Aug 2015 16:39:36 AFT +04:30
When supliyng an API
Time.current.utc.iso8601
2015-08-27T12:09:36Z
If you can’t use Time.zone.parse
Time.strptime("2015-08-27T12:09:36Z", "%Y-%m-%dT%H:%M:%S%z").in_time_zone
Thu, 27 Aug 2015 16:39:36 AFT +04:30
If you really can’t have a Time or DateTime for some reason
Date.current
Thu, 27 Aug 2015
If you have a date and want to make the best out of it
Date.current.in_time_zone
Thu, 27 Aug 2015 00:00:00 AFT +04:30
DON’Ts
code
result
Returns system time and ignores your configured time zone.
Time.now
2015-08-27 14:09:36 +0200
Will assume time string given is in the system’s time zone.
Time.parse("2015-08-27T12:09:36Z")
2015-08-27 12:09:36 UTC
Same problem as with Time.parse.
Time.strptime("2015-08-27T12:09:36Z", "%Y-%m-%dT%H:%M:%S%z")
2015-08-27 12:09:36 UTC
This could be yesterday or tomorrow depending on the machine’s time zone, see issue 1 for more info.
Date.today
Thu, 27 Aug 2015
Time.now - using server time
Time.zone.now - using rails application time (in config: config.time_zone)
Time.use_zone - using 'your' timezone for given block
This example is wrong, because Time.now get time in your server timezone and with method in_time_zone translate time into an equivalent time in Hawaii timezone. But it's no current Time in Hawaii! It's your server time with utc offset for Hawaii.
Time.use_zone('Hawaii') do
Time.now.in_time_zone
end
=> Wed, 14 Aug 2013 10:33:18 HST -10:00
Time.now.in_time_zone
=> Thu, 15 Aug 2013 00:32:30 MSK +04:00
For getting time in Hawaii timezone you must use
Time.use_zone('Hawaii') do
Time.zone.now
end
Don't use Time.now this is using your local time zone instead use Time.current
Time.use_zone('Hawaii') do
p Time.current
end