Convert data/time string in Ruby - ruby-on-rails

I am trying to convert a date/time string "06/14/2016 07:00 PM" to a Time object under the PST time zone. I want the result to be Tue, 14 Jun 2016 19:00:00 PDT -07:00.
I tried the following:
t = "06/14/2016 07:00 PM"
r = Time.strptime(t, "%m/%d/%Y %I:%M %p").in_time_zone("Pacific Time (US & Canada)")
The time comes back as Tue, 14 Jun 2016 17:00:00 PDT -07:00. Any ideas?

This code to me works properly, but there are two possible issues that are giving you the wrong result:
You are not in the pacific time zone (or at least not according to your computer): You can test this by running r = Time.strptime(t, "%m/%d/%Y %I:%M %p"), and then printing the result of r. I'm willing to wager that it outputs
Tue, 14 Jun 2016 19:00:00 CDT -05:00
You are using ruby and not rails, in_time_zone is a method only in rails. If you try to use it in ruby it will not work.

Related

Parse Time in Ruby

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

Ruby parse DateTime with variable

I'm trying to parse a specific hour of a specific date. When I put the date directly as an argument, it works fine, but when I create a variable and put it in the argument it returns the current date.
Why is that?
NOTE: the variable time is 9pm and I need to parse 9pm of 12 March 2016.
datetime = DateTime.new(2016,3,12,9)
=> Sat, 12 Mar 2016 09:00:00 +0000
DateTime.parse("sat 12 march 2016 9pm")
=> Sat, 12 Mar 2016 21:00:00 +0000
DateTime.parse("datetime 9pm")
=> Mon, 14 Mar 2016 21:00:00 +0000
In your third call, you use the literal string "datetime" rather than the value of your datetime variable. You can use string interpolation to use the variable's value:
DateTime.parse("#{datetime} 9pm")
In this case, the "9pm" is ignored since it doesn't make sense added to the end of an existing date but this is why the initial attempt wasn't working. Interpolation is generally a solution for using a variable's value rather than its name.
If your goal is to change the time of an existing date, use the change method:
datetime.change(hour:21)
You can also try this
date = Date.new(2016,3,12)
DateTime.parse("#{date} 9pm")
## Output
Sat, 12 Mar 2016 21:00:00 +0000
OR
datetime = DateTime.new(2016,3,12,9)
DateTime.parse((datetime + 12.hours).to_s)
## Output
Sat, 12 Mar 2016 21:00:00 +0000
OR
DateTime.parse((datetime + 12.hours).to_s).strftime("%a, %d %b %Y %I:%M %p")
## Output
Sat, 12 Mar 2016 09:00 PM

Invalid date getting displayed in rails

I know it is common error but I could not resolve it even after trying those answers.
Through the rest api I am sending some parameters inculdes dates. I am recieving all the data in the method where I want but when I am trying to parse Date it throws error of invalid date.
Here are my parameters that I am recieving
{"uid"=>"1", "user"=>"abc.a#abc.com", "from"=>"Mon Nov 3 24:59:12 CET 2014", "to"=>"Tue Nov 11 24:59:12 CET 2014"}
and Date format is
Mon Nov 3 24:59:12 CET 2014
but it is throwing error on parsing on line below
fr = DateTime.parse(params[:from]) unless params[:from].empty?
I tried strptime as well but did not work.
Imp points is I need hour also for later processing. Thanks
what you are doing wrong is parsing DateTime while it is just date and should be parsed as one of the following ways:
1.
>> fr = params[:from].to_date unless params[:from].empty?
=> Mon, 03 Nov 2014
2.
>> fr = Date.parse(params[:from]) unless params[:from].empty?
=> Mon, 03 Nov 2014
You have 24:59 which is invalid time. Anyway, use strptime:
DateTime.strptime("Mon Nov 3 22:59:12 CET 2014", "%a %b %e %T %Z %Y")
#=> Mon, 03 Nov 2014 22:59:12 +0100

Time.use_zone is not working as expected

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

Rails 3.1.1 timezone behaviour

I have a problem related to timezone behaviour of a Rails 3.1.1 application. Here is, what I did on my console:
(rdb:1) Time.zone = "Amsterdam"
"Amsterdam"
(rdb:1) Time.zone.parse("Sun, 06 Nov 2011 13:05:18 +0000")
Sun, 06 Nov 2011 14:05:18 CET +01:00
(rdb:1) Time.zone = "Atlantic Time (Canada)"
"Atlantic Time (Canada)"
(rdb:1) Time.zone.parse("Sun, 06 Nov 2011 13:05:18 +0000")
Sun, 06 Nov 2011 09:05:18 AST -04:00
My object's timestamp is UTC. In my timezone Amsterdam it was 14:05 when I created it. In New York City the timezone is "Atlantic Time (Canada)". Parsing the timestamp in that zone results in 09:05. But thats wrong, it should be 08:05.
Besides that the time difference between both zones seems to be -4 -1 = -5 but is in fact -6 hours.
That behaviour completely destroy's my apps behaviour. What am I doing wrong here?
Regards
Felix.
You are not doing anything wrong. The DST changed today, Nov 6, at 2 AM. So the time is 9:05, and not 8:05. Also, New York is in Eastern time, not Atlantic time.

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