Ruby on Rails: how do I convert this date - ruby-on-rails

Wed Sep 22 13:15:02 -0400 2010 to this format 2010-08-23 13:15:02 -0400
The left is Time.now
The right is 30.days.ago =\

You can use the to_s(:db) method in Time class to convert it to a database-friendly format.
Time.now.to_s(:db) # => "2010-09-22 17:50:41"
If you really need the time zone offset info, you could add a custom format to Time::DATE_FORMATS, e.g.
Time::DATE_FORMATS[:db_with_zone_offset] = lambda { |time|
time.strftime("%Y-%m-%d %H:%M:%S #{time.formatted_offset(false)}")
}
after which you can simply call
Time.now.to_s(:db_with_zone_offset) => # "2010-09-22 17:48:21 +0000"

Both are different data types.
>> Time.now.class
=> Time
>> 30.days.ago.class
=> ActiveSupport::TimeWithZone
use the strftime method to format it.

If you want to have format in database format, then you can use:
Time.now
=> Wed Sep 22 19:54:24 +0200 2010
Time.now.to_s(:db)
=> "2010-09-22 19:54:48"
Time.now.utc.to_s(:db)
=> "2010-09-22 17:55:16"

Related

Convert Active Support timezone original format into a string

I'm trying to convert Active Support timezone original format into a string. I want to store it in an array of characters then parse each needed data individually.
Time.zone = current_user.timezone
date_and_time = Time.zone.now
Now
date_and_time = Thu, 21 Apr 2016 20:58:04 PDT -07:00
Ruby method ( to_s ) does not convert it. I found other ways to convert it to but all of them will change the format to numbers only, I want the day to stay the same because I will store it in a variable then use it in a different method.
You can use .to_formatted_s(DATE_FORMAT) for this.
time = Time.now # => Thu Jan 18 06:10:17 CST 2007
time.to_formatted_s(:db) # => "2007-01-18 06:10:17"
time.to_formatted_s(:long) # => "January 18, 2007 06:10"
time.to_formatted_s(:long_ordinal) # => "January 18th, 2007 06:10"
time.to_formatted_s(:rfc822) # => "Thu, 18 Jan 2007 06:10:17 -0600"
time.to_formatted_s(:iso8601) # => "2007-01-18T06:10:17-06:00"
A list of all DATE_FORMATS and more information can be found here:
http://api.rubyonrails.org/classes/Time.html#method-i-to_formatted_s
You can try this
date_and_time.strftime("%a %d %b %Y")
Also You can check this guide, to get format you want
You should get what you want using this :
date_and_time.strftime("%a %d %b %Y %H:%M:%S UTC %:z")
Please see strftime Docs for more info
Explanation
Reason for hardcoding UTC is so that according to the docs
%z - Time zone as hour and minute offset from UTC
So i believe it should be UTC all the time.

Ruby parse time zone string FORMAT for DB

I am trying to parse a string that's hitting my api. The incoming string is
"2014-03-19T04:00:00.000Z"
I need it in the following format for my db sql to work:
"2014-03-19 00:00:00 -0400"
Right now, the solution I have come up with is
Time.zone.parse("2014-03-19T04:00:00.000Z").in_time_zone('America/New_York').to_s
This feels like an inelegant solution to me and I feel that there should be a more dynamic way of doing things without specifying the time zone name (it should be local by default). I just want to switch the formatting of the strings as they are supposed to be equivalent.
Thanks
Configure the time_zone in the application.rb file and use it as below:
# application.rb:
class Application < Rails::Application
config.time_zone = 'America/New_York'
end
Time.zone.parse("2014-03-19T04:00:00.000Z").to_s
# => "2014-03-19 00:00:00 -0400"
More examples of use
$ > Time.zone = "America/New_York"
# => "America/New_York"
$ > Time.zone
# => (GMT-05:00) America/New_York
$ > Time.zone.now
# => Sat, 22 Mar 2014 18:28:48 EDT -04:00
irb(main):008:0> Time.parse("2014-03-19T04:00:00.000Z").getlocal.strftime("%F %T %z")
=> "2014-03-19 04:00:00 +0000"
On a system in GMT+1:
irb(main):003:0> Time.parse("2014-03-19T04:00:00.000Z").getlocal.strftime("%F %T %z")
=> "2014-03-19 05:00:00 +0100"

Ruby / Rails - Change the timezone of a Time, without changing the value

I have a record foo in the database which has :start_time and :timezone attributes.
The :start_time is a Time in UTC - 2001-01-01 14:20:00, for example.
The :timezone is a string - America/New_York, for example.
I want to create a new Time object with the value of :start_time but whose timezone is specified by :timezone. I do not want to load the :start_time and then convert to :timezone, because Rails will be clever and update the time from UTC to be consistent with that timezone.
Currently,
t = foo.start_time
=> 2000-01-01 14:20:00 UTC
t.zone
=> "UTC"
t.in_time_zone("America/New_York")
=> Sat, 01 Jan 2000 09:20:00 EST -05:00
Instead, I want to see
=> Sat, 01 Jan 2000 14:20:00 EST -05:00
ie. I want to do:
t
=> 2000-01-01 14:20:00 UTC
t.zone = "America/New_York"
=> "America/New_York"
t
=> 2000-01-01 14:20:00 EST
Sounds like you want something along the lines of
ActiveSupport::TimeZone.new('America/New_York').local_to_utc(t)
This says convert this local time (using the zone) to utc. If you have Time.zone set then you can of course to
Time.zone.local_to_utc(t)
This won't use the timezone attached to t - it assumes that it's local to the time zone you are converting from.
One edge case to guard against here is DST transitions: the local time you specify may not exist or may be ambiguous.
I've just faced the same problem and here is what I'm going to do:
t = t.asctime.in_time_zone("America/New_York")
Here is the documentation on asctime
If you're using Rails, here is another method along the lines of Eric Walsh's answer:
def set_in_timezone(time, zone)
Time.use_zone(zone) { time.to_datetime.change(offset: Time.zone.now.strftime("%z")) }
end
You need to add the time offset to your time after you convert it.
The easiest way to do this is:
t = Foo.start_time.in_time_zone("America/New_York")
t -= t.utc_offset
I am not sure why you would want to do this, though it is probably best to actually work with times the way they are built. I guess some background on why you need to shift time and timezones would be helpful.
Actually, I think you need to subtract the offset after you convert it, as in:
1.9.3p194 :042 > utc_time = Time.now.utc
=> 2013-05-29 16:37:36 UTC
1.9.3p194 :043 > local_time = utc_time.in_time_zone('America/New_York')
=> Wed, 29 May 2013 12:37:36 EDT -04:00
1.9.3p194 :044 > desired_time = local_time-local_time.utc_offset
=> Wed, 29 May 2013 16:37:36 EDT -04:00
Depends on where you are going to use this Time.
When your time is an attribute
If time is used as an attribute, you can use the same date_time_attribute gem:
class Task
include DateTimeAttribute
date_time_attribute :due_at
end
task = Task.new
task.due_at_time_zone = 'Moscow'
task.due_at # => Mon, 03 Feb 2013 22:00:00 MSK +04:00
task.due_at_time_zone = 'London'
task.due_at # => Mon, 03 Feb 2013 22:00:00 GMT +00:00
When you set a separate variable
Use the same date_time_attribute gem:
my_date_time = DateTimeAttribute::Container.new(Time.zone.now)
my_date_time.date_time # => 2001-02-03 22:00:00 KRAT +0700
my_date_time.time_zone = 'Moscow'
my_date_time.date_time # => 2001-02-03 22:00:00 MSK +0400
Here's another version that worked better for me than the current answers:
now = Time.now
# => 2020-04-15 12:07:10 +0200
now.strftime("%F %T.%N").in_time_zone("Europe/London")
# => Wed, 15 Apr 2020 12:07:10 BST +01:00
It carries over nanoseconds using "%N". If you desire another precision, see this strftime reference.
The question's about Rails but it seems, like me, not everyone here is on the ActiveSupport train, so yet another option:
irb(main):001:0> require "time"
=> true
irb(main):003:0> require "tzinfo"
=> true
irb(main):004:0> t = Time.parse("2000-01-01 14:20:00 UTC")
=> 2000-01-01 14:20:00 UTC
irb(main):005:0> tz = TZInfo::Timezone.get("America/New_York")
=> #<TZInfo::DataTimezone: America/New_York>
irb(main):008:0> utc = tz.local_to_utc(t)
=> 2000-01-01 19:20:00 UTC
irb(main):009:0> tz.utc_to_local(utc)
=> 2000-01-01 14:20:00 -0500
irb(main):010:0>
local_to_utc not doing the opposite of utc_to_local might look like a bug but it is at least documented: https://github.com/tzinfo/tzinfo says:
The offset of the time is ignored - it is treated as if it were a local time for the time zone
I managed to do this by calling change with the desired time zone:
>> t = Time.current.in_time_zone('America/New_York')
=> Mon, 08 Aug 2022 12:04:36.934007000 EDT -04:00
>> t.change(zone: 'Etc/UTC')
=> Mon, 08 Aug 2022 12:04:36.934007000 UTC +00:00
https://api.rubyonrails.org/classes/ActiveSupport/TimeWithZone.html#method-i-change
def relative_time_in_time_zone(time, zone)
DateTime.parse(time.strftime("%d %b %Y %H:%M:%S #{time.in_time_zone(zone).formatted_offset}"))
end
Quick little function I came up with to solve the job. If someone has a more efficient way of doing this please post it!
I spent significant time struggling with TimeZones as well, and after tinkering with Ruby 1.9.3 realized that you don't need to convert to a named timezone symbol before converting:
my_time = Time.now
west_coast_time = my_time.in_time_zone(-8) # Pacific Standard Time
east_coast_time = my_time.in_time_zone(-5) # Eastern Standard Time
What this implies is that you can focus on getting the appropriate time setup first in the region you want, the way you would think about it (at least in my head I partition it this way), and then convert at the end to the zone you want to verify your business logic with.
This also works for Ruby 2.3.1.
I have created few helper methods one of which just does the same thing as is asked by the original author of the post at Ruby / Rails - Change the timezone of a Time, without changing the value.
Also I have documented few peculiarities I observed and also these helpers contains methods to completely ignore automatic day-light savings applicable while time-conversions which is not available out-of-the-box in Rails framework:
def utc_offset_of_given_time(time, ignore_dst: false)
# Correcting the utc_offset below
utc_offset = time.utc_offset
if !!ignore_dst && time.dst?
utc_offset_ignoring_dst = utc_offset - 3600 # 3600 seconds = 1 hour
utc_offset = utc_offset_ignoring_dst
end
utc_offset
end
def utc_offset_of_given_time_ignoring_dst(time)
utc_offset_of_given_time(time, ignore_dst: true)
end
def change_offset_in_given_time_to_given_utc_offset(time, utc_offset)
formatted_utc_offset = ActiveSupport::TimeZone.seconds_to_utc_offset(utc_offset, false)
# change method accepts :offset option only on DateTime instances.
# and also offset option works only when given formatted utc_offset
# like -0500. If giving it number of seconds like -18000 it is not
# taken into account. This is not mentioned clearly in the documentation
# , though.
# Hence the conversion to DateTime instance first using to_datetime.
datetime_with_changed_offset = time.to_datetime.change(offset: formatted_utc_offset)
Time.parse(datetime_with_changed_offset.to_s)
end
def ignore_dst_in_given_time(time)
return time unless time.dst?
utc_offset = time.utc_offset
if utc_offset < 0
dst_ignored_time = time - 1.hour
elsif utc_offset > 0
dst_ignored_time = time + 1.hour
end
utc_offset_ignoring_dst = utc_offset_of_given_time_ignoring_dst(time)
dst_ignored_time_with_corrected_offset =
change_offset_in_given_time_to_given_utc_offset(dst_ignored_time, utc_offset_ignoring_dst)
# A special case for time in timezones observing DST and which are
# ahead of UTC. For e.g. Tehran city whose timezone is Iran Standard Time
# and which observes DST and which is UTC +03:30. But when DST is active
# it becomes UTC +04:30. Thus when a IRDT (Iran Daylight Saving Time)
# is given to this method say '05-04-2016 4:00pm' then this will convert
# it to '05-04-2016 5:00pm' and update its offset to +0330 which is incorrect.
# The updated UTC offset is correct but the hour should retain as 4.
if utc_offset > 0
dst_ignored_time_with_corrected_offset -= 1.hour
end
dst_ignored_time_with_corrected_offset
end
Examples which can be tried on rails console or a ruby script after wrapping the above methods in a class or module:
dd1 = '05-04-2016 4:00pm'
dd2 = '07-11-2016 4:00pm'
utc_zone = ActiveSupport::TimeZone['UTC']
est_zone = ActiveSupport::TimeZone['Eastern Time (US & Canada)']
tehran_zone = ActiveSupport::TimeZone['Tehran']
utc_dd1 = utc_zone.parse(dd1)
est_dd1 = est_zone.parse(dd1)
tehran_dd1 = tehran_zone.parse(dd1)
utc_dd1.dst?
est_dd1.dst?
tehran_dd1.dst?
ignore_dst = true
utc_to_est_time = utc_dd1.in_time_zone(est_zone.name)
if utc_to_est_time.dst? && !!ignore_dst
utc_to_est_time = ignore_dst_in_given_time(utc_to_est_time)
end
puts utc_to_est_time
Hope this helps.
This worked well for me
date = '23/11/2020'
time = '08:00'
h, m = time.split(':')
timezone = 'Europe/London'
date.to_datetime.in_time_zone(timezone).change(hour: h, min: m)
This changes the timezone to 'EST' without changing the time:
time = DateTime.current
Time.find_zone("EST").local(
time.year,
time.month,
time.day,
time.hour,
time.min,
time.sec,
)

Ruby on Rails - how to display a date in format i need? Converting from YYYY-MM-DD HH:MM:SS UTC to MM/DD/YYYY

I am a RoR newbie. I tried a lot of things, finally came to following:
<td>
<%= Date.strptime(request.baseline_start_date, "%Y-%M-%D %H:%M:%S %Z").strftime("%M/%D/%Y")%>
</td>
But this is also giving me an error:
$_ value need to be String (nil given)
But I know that request.baseline_start_date gives me value (tried printing it separately). I don't know which one it is saying as nil given.
Any suggestions on how I can achieve format conversion?
In Rails you can use the to_time function on a string to convert it into a Date object:
'2012-11-14 14:27:46'.to_time.strftime('%B %e at %l:%M %p')
#=> "November 14 at 2:27 PM"
For a handy, interactive reference guide, refer to http://www.foragoodstrftime.com/
Date.strptime(
"2009-04-24 18:33:41 UTC",
"%Y-%m-%d %H:%M:%S %Z"
).strftime("%m/%d/%Y")
# => "04/24/2009"
I think maybe you just got the capitalization on your format strings wrong.
Check the active support documentation and examples at:
http://apidock.com/rails/ActiveSupport/CoreExtensions/DateTime/Conversions/to_formatted_s
Examples
datetime = DateTime.civil(2007, 12, 4, 0, 0, 0, 0) # => Tue, 04 Dec 2007 00:00:00 +0000
datetime.to_formatted_s(:db) # => "2007-12-04 00:00:00"
datetime.to_s(:db) # => "2007-12-04 00:00:00"
datetime.to_s(:number) # => "20071204000000"
datetime.to_formatted_s(:short) # => "04 Dec 00:00"
datetime.to_formatted_s(:long) # => "December 04, 2007 00:00"
datetime.to_formatted_s(:long_ordinal) # => "December 4th, 2007 00:00"
datetime.to_formatted_s(:rfc822) # => "Tue, 04 Dec 2007 00:00:00 +0000"
Or if you really want to customise it, define the helper like:
def custom_format(time)
Time::DATE_FORMATS[:w3cdtf] = lambda { |time| time.strftime("%Y-%m-%dT%H:%M:%S# {time.formatted_offset}") }
end
You can use the String#to_time (or Date#to_time) function in ActiveSupport to convert the string into a Time (or Date) object. Then use strftime as you have already.
Ive written a really nice gem that simplifies the whole process, and makes date formatting DRY.
Check it out at:
http://github.com/platform45/easy_dates
What I have done is add an initializer named conversions.rb in config/initializer
After that Add a line like follows:
ActiveSupport::CoreExtensions::Time::Conversions::DATE_FORMATS.update(:<name> => '<formatting>')
From there on you can render your datetime using your format with:
dateVar.to_s(:<name>)
There is a handy list here of the formatting tokens
Thanks a lot for the reply. My problem is, the output seems to be already string and i have to convert from date in string to another format.
When I look at the date stored in database (Oracle) it is mm/dd/yy, but when i get it displayed, it adds the timestamp and timezone.
I tried setting the default in Configuration\environment.rb as
ActiveSupport::CoreExtensions::Date::Conversions::DATE_FORMATS.merge!(
:default => '%d %b %Y'
)
But that also doesn't seem to help.
At the end, if I just get the string to convert from Timezone format to mm/dd/yyyy, that is enough.

In Ruby on Rails, how do I format a date with the "th" suffix, as in, "Sun Oct 5th"?

I want to display dates in the format: short day of week, short month, day of month without leading zero but including "th", "st", "nd", or "rd" suffix.
For example, the day this question was asked would display "Thu Oct 2nd".
I'm using Ruby 1.8.7, and Time.strftime just doesn't seem to do this. I'd prefer a standard library if one exists.
Use the ordinalize method from 'active_support'.
>> time = Time.new
=> Fri Oct 03 01:24:48 +0100 2008
>> time.strftime("%a %b #{time.day.ordinalize}")
=> "Fri Oct 3rd"
Note, if you are using IRB with Ruby 2.0, you must first run:
require 'active_support/core_ext/integer/inflections'
You can use active_support's ordinalize helper method on numbers.
>> 3.ordinalize
=> "3rd"
>> 2.ordinalize
=> "2nd"
>> 1.ordinalize
=> "1st"
Taking Patrick McKenzie's answer just a bit further, you could create a new file in your config/initializers directory called date_format.rb (or whatever you want) and put this in it:
Time::DATE_FORMATS.merge!(
my_date: lambda { |time| time.strftime("%a, %b #{time.day.ordinalize}") }
)
Then in your view code you can format any date simply by assigning it your new date format:
My Date: <%= h some_date.to_s(:my_date) %>
It's simple, it works, and is easy to build on. Just add more format lines in the date_format.rb file for each of your different date formats. Here is a more fleshed out example.
Time::DATE_FORMATS.merge!(
datetime_military: '%Y-%m-%d %H:%M',
datetime: '%Y-%m-%d %I:%M%P',
time: '%I:%M%P',
time_military: '%H:%M%P',
datetime_short: '%m/%d %I:%M',
due_date: lambda { |time| time.strftime("%a, %b #{time.day.ordinalize}") }
)
>> require 'activesupport'
=> []
>> t = Time.now
=> Thu Oct 02 17:28:37 -0700 2008
>> formatted = "#{t.strftime("%a %b")} #{t.day.ordinalize}"
=> "Thu Oct 2nd"
Although Jonathan Tran did say he was looking for the abbreviated day of the week first followed by the abbreviated month, I think it might be useful for people who end up here to know that Rails has out-of-the-box support for the more commonly usable long month, ordinalized day integer, followed by the year, as in June 1st, 2018.
It can be easily achieved with:
Time.current.to_date.to_s(:long_ordinal)
=> "January 26th, 2019"
Or:
Date.current.to_s(:long_ordinal)
=> "January 26th, 2019"
You can stick to a time instance if you wish as well:
Time.current.to_s(:long_ordinal)
=> "January 26th, 2019 04:21"
You can find more formats and context on how to create a custom one in the Rails API docs.
Create your own %o format.
Initializer
config/initializers/srtftime.rb
module StrftimeOrdinal
def self.included( base )
base.class_eval do
alias_method :old_strftime, :strftime
def strftime( format )
old_strftime format.gsub( "%o", day.ordinalize )
end
end
end
end
[ Time, Date, DateTime ].each{ |c| c.send :include, StrftimeOrdinal }
Usage
Time.new( 2018, 10, 2 ).strftime( "%a %b %o" )
=> "Tue Oct 2nd"
You can use this with Date and DateTime as well:
DateTime.new( 2018, 10, 2 ).strftime( "%a %b %o" )
=> "Tue Oct 2nd"
Date.new( 2018, 10, 2 ).strftime( "%a %b %o" )
=> "Tue Oct 2nd"
I like Bartosz's answer, but hey, since this is Rails we're talking about, let's take it one step up in devious. (Edit: Although I was going to just monkeypatch the following method, turns out there is a cleaner way.)
DateTime instances have a to_formatted_s method supplied by ActiveSupport, which takes a single symbol as a parameter and, if that symbol is recognized as a valid predefined format, returns a String with the appropriate formatting.
Those symbols are defined by Time::DATE_FORMATS, which is a hash of symbols to either strings for the standard formatting function... or procs. Bwahaha.
d = DateTime.now #Examples were executed on October 3rd 2008
Time::DATE_FORMATS[:weekday_month_ordinal] =
lambda { |time| time.strftime("%a %b #{time.day.ordinalize}") }
d.to_formatted_s :weekday_month_ordinal #Fri Oct 3rd
But hey, if you can't resist the opportunity to monkeypatch, you could always give that a cleaner interface:
class DateTime
Time::DATE_FORMATS[:weekday_month_ordinal] =
lambda { |time| time.strftime("%a %b #{time.day.ordinalize}") }
def to_my_special_s
to_formatted_s :weekday_month_ordinal
end
end
DateTime.now.to_my_special_s #Fri Oct 3rd

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