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).
Related
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"))
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
Ruby correctly parses the first date but the second one is incorrect. Tested with ruby 1.9.3 and 2.1.2.
Any idea how to get it to work consistently? (We are getting in birth dates as 2 digit years)
Date.strptime("10/11/89","%d/%m/%y")
=> Fri, 10 Nov 1989
Date.strptime("15/10/63","%d/%m/%y")
=> Mon, 15 Oct 2063
The strptime method is parsing the text "63" to the year 2063, not 1963 as you want.
This is because the method decides the century by using the POSIX standard.
The chronic gem has a similar issue because it decides the century, though differently.
A solution is to adjust the date:
d = Date.strptime("15/10/63","%d/%m/%y")
if d > Date.today
d = Date.new(d.year - 100, d.month, d.mday)
end
In the comments of this post, Stefan suggests a good one liner:
d = d.prev_year(100) if d > Date.today
If you need speed, you can try optimizing like this:
d <= Date.today || d = d << 1200
When using %y in strptime, the code assumes that values under 68 are considered in the 21st century, as descirbed here:
The year within century (0-99). When a century is not otherwise specified (with a value for %C), values in the range 69-99 refer to years in the twentieth century (1969-1999); values in the range 00-68 refer to years in the twenty-first century (2000-2068).
In the chronic gem, incidentally, the cut-off year is 64:
Chronic.parse('15/10/64')
# => 1964-10-15 12:00:00 +0200
Chronic.parse('15/10/63')
# => 2063-10-15 12:00:00 +0300
Chronic gem has added an extended support parsing 2 digit years with ambiguous_year_future_bias option:
irb(main):029:0> Chronic.parse('15/10/99', ambiguous_year_future_bias: 10)
=> 2099-10-15 12:00:00 +0300
irb(main):030:0> Chronic.parse('15/10/99', ambiguous_year_future_bias: 50)
=> 1999-10-15 12:00:00 +0300
Add the Chronic gem to your Gemfile
gem 'chronic'
Then just parse it:
Chronic.parse("15/10/68")
=> 1968-10-15 12:00:00 -0700
I have a text_field :birthday_line in my user form, that I need to parse into the user's birthday attribute.
So I'm doing something like this in my User class.
attr_accessor :birthday_line
before_save :set_birthday
def set_birthday
self.birthday = Date.strptime(birthday_line, I18n.translate("date.formats.default")
end
But the problem is that for some reason it gives me an error saying Invalid date when I try to pass in a string 27 января 1987 г. wich should be parsed to 1987-01-27.
The format and month names in my config/locales/ru.yml
ru:
date:
formats:
default: "%d %B %Y г."
month_names: [~, января, февраля, марта, апреля, мая, июня, июля, августа, сентября, октября, ноября, декабря]
seem to be correct.
Date.parse also doesn't help, it just parses the day number (27) and puts the month and year to todays date (so it'll be September 27 2013 instead of January 27 1987).
I had the same problem and what I can suggest:
string_with_cyrillic_date = '27 Января 1987'
1)create array of arrays like this
months = [["января", "Jan"], ["февраля", "Feb"], ["марта", "Mar"], ["апреля", "Apr"], ["мая", "May"], ["июня", "Jun"], ["июля", "Jul"], ["августа", "Aug"], ["сентября", "Sep"], ["октября", "Oct"], ["ноября", "Nov"], ["декабря", "Dec"]]
2) Now you can iterate this and find your cyrillic month:
months.each do |cyrillic_month, latin_month|
if string_with_cyrillic_date.match cyrillic_month
DateTime.parse string_with_cyrillic_date.gsub!(/#{cyrillic_month}/, latin_month)
end
end
And now you will receive the date that you expect
27 Jan 1987
I would like to know how to get the current week number from Rails and how do I manipulate it:
Translate the week number into date.
Make an interval based on week number.
Thanks.
Use strftime:
%U - Week number of the year. The week starts with Sunday. (00..53)
%W - Week number of the year. The week starts with Monday. (00..53)
Time.now.strftime("%U").to_i # 43
# Or...
Date.today.strftime("%U").to_i # 43
If you want to add 43 weeks (or days,years,minutes, etc...) to a date, you can use 43.weeks, provided by ActiveSupport:
irb(main):001:0> 43.weeks
=> 301 days
irb(main):002:0> Date.today + 43.weeks
=> Thu, 22 Aug 2013
irb(main):003:0> Date.today + 10.days
=> Sun, 04 Nov 2012
irb(main):004:0> Date.today + 1.years # or 1.year
=> Fri, 25 Oct 2013
irb(main):005:0> Date.today + 5.months
=> Mon, 25 Mar 2013
You are going to want to stay away from strftime("%U") and "%W".
Instead, use Date.cweek.
The problem is, if you ever want to take a week number and convert it to a date, strftime won't give you a value that you can pass back to Date.commercial.
Date.commercial expects a range of values that are 1 based.
Date.strftime("%U|%W") returns a value that is 0 based. You would think you could just +1 it and it would be fine. The problem will hit you at the end of a year when there are 53 weeks. (Like what just happened...)
For example, let's look at the end of Dec 2015 and the results from your two options for getting a week number:
Date.parse("2015-12-31").strftime("%W") = 52
Date.parse("2015-12-31").cweek = 53
Now, let's look at converting that week number to a date...
Date.commercial(2015, 52, 1) = Mon, 21 Dec 2015
Date.commercial(2015, 53, 1) = Mon, 28 Dec 2015
If you blindly just +1 the value you pass to Date.commercial, you'll end up with an invalid date in other situations:
For example, December 2014:
Date.commercial(2014, 53, 1) = ArgumentError: invalid date
If you ever have to convert that week number back to a date, the only surefire way is to use Date.cweek.
date.commercial([cwyear=-4712[, cweek=1[, cwday=1[, start=Date::ITALY]]]]) → date
Creates a date object denoting the given week date.
The week and the day of week should be a negative
or a positive number (as a relative week/day from the end of year/week when negative).
They should not be zero.
For the interval
require 'date'
def week_dates( week_num )
year = Time.now.year
week_start = Date.commercial( year, week_num, 1 )
week_end = Date.commercial( year, week_num, 7 )
week_start.strftime( "%m/%d/%y" ) + ' - ' + week_end.strftime("%m/%d/%y" )
end
puts week_dates(22)
EG: Input (Week Number): 22
Output: 06/12/08 - 06/19/08
credit: Siep Korteling http://www.ruby-forum.com/topic/125140
Date#cweek seems to get the ISO-8601 week number (a Monday-based week) like %V in strftime (mentioned by #Robban in a comment).
For example, the Monday and the Sunday of the week I'm writing this:
[ Date.new(2015, 7, 13), Date.new(2015, 7, 19) ].map { |date|
date.strftime("U: %U - W: %W - V: %V - cweek: #{date.cweek}")
}
# => ["U: 28 - W: 28 - V: 29 - cweek: 29", "U: 29 - W: 28 - V: 29 - cweek: 29"]