How to convert a unix timestamp (seconds since epoch) to Ruby DateTime?
如何将Unix时间戳记（自epoch以来的秒数）转换为Ruby DateTime？
DateTime.strptime can handle seconds since epoch. The number must be converted to a string:
require 'date'
DateTime.strptime("1318996912",'%s')
Sorry, brief moment of synapse failure. Here's the real answer.
require 'date'
Time.at(seconds_since_epoch_integer).to_datetime
Brief example (this takes into account the current system timezone):
$ date +%s
1318996912
$ irb
ruby-1.9.2-p180 :001 > require 'date'
=> true
ruby-1.9.2-p180 :002 > Time.at(1318996912).to_datetime
=> #<DateTime: 2011-10-18T23:01:52-05:00 (13261609807/5400,-5/24,2299161)>
Further update (for UTC):
ruby-1.9.2-p180 :003 > Time.at(1318996912).utc.to_datetime
=> #<DateTime: 2011-10-19T04:01:52+00:00 (13261609807/5400,0/1,2299161)>
Recent Update : I benchmarked the top solutions in this thread while working on a HA service a week or two ago, and was surprised to find that Time.at(..) outperforms DateTime.strptime(..) (update: added more benchmarks).
# ~ % ruby -v
# => ruby 2.1.5p273 (2014-11-13 revision 48405) [x86_64-darwin13.0]
irb(main):038:0> Benchmark.measure do
irb(main):039:1* ["1318996912", "1318496912"].each do |s|
irb(main):040:2* DateTime.strptime(s, '%s')
irb(main):041:2> end
irb(main):042:1> end
=> #<Benchmark ... @real=2.9e-05 ... @total=0.0>
irb(main):044:0> Benchmark.measure do
irb(main):045:1> [1318996912, 1318496912].each do |i|
irb(main):046:2> DateTime.strptime(i.to_s, '%s')
irb(main):047:2> end
irb(main):048:1> end
=> #<Benchmark ... @real=2.0e-05 ... @total=0.0>
irb(main):050:0* Benchmark.measure do
irb(main):051:1* ["1318996912", "1318496912"].each do |s|
irb(main):052:2* Time.at(s.to_i).to_datetime
irb(main):053:2> end
irb(main):054:1> end
=> #<Benchmark ... @real=1.5e-05 ... @total=0.0>
irb(main):056:0* Benchmark.measure do
irb(main):057:1* [1318996912, 1318496912].each do |i|
irb(main):058:2* Time.at(i).to_datetime
irb(main):059:2> end
irb(main):060:1> end
=> #<Benchmark ... @real=2.0e-05 ... @total=0.0>
Time Zone Handling
I just want to clarify, even though this has been commented so future people don't miss this very important distinction.
DateTime.strptime("1318996912",'%s') # => Wed, 19 Oct 2011 04:01:52 +0000
displays a return value in UTC and requires the seconds to be a String and outputs a UTC Time object, whereas
Time.at(1318996912) # => 2011-10-19 00:01:52 -0400
displays a return value in the LOCAL time zone, normally requires a FixNum argument, but the Time object itself is still in UTC even though the display is not.
So even though I passed the same integer to both methods, I seemingly two different results because of how the class' #to_s method works. However, as @Eero had to remind me twice of:
Time.at(1318996912) == DateTime.strptime("1318996912",'%s') # => true
An equality comparison between the two return values still returns true. Again, this is because the values are basically the same (although different class's, the #== method takes care of this for you), but the #to_s method prints drastically different strings. Although, if we look at the strings, we can see they are indeed the same time, just printed in different time zones.
Method Argument Clarification
The docs also say "If a numeric argument is given, the result is in local time." which makes sense, but was a little confusing to me because they don't give any examples of non-integer arguments in the docs. So, for some non-integer argument examples:
Time.at("1318996912")
TypeError: can't convert String into an exact number
you can't use a String argument, but you can use a Time argument into Time.at and it will return the result in the time zone of the argument:
Time.at(Time.new(2007,11,1,15,25,0, "+09:00"))
=> 2007-11-01 15:25:00 +0900
****edited to not be completely and totally incorrect in every way****
链接地址: http://www.djcxy.com/p/4270.html上一篇: 将本地分支与git存储库中的远程分支同步