Ruby 一些有用的代码整理(持续更新)

时间相关

DateTime 计算时间前后几天/几小时

• 一天前: DateTime.now - 1
• 一个小时前: DateTime.now - 1/24.0

示例:

#创建时间
d = DateTime.now
=> #<DateTime: 2019-02-20T15:15:30+09:00 ((2458535j,22530s,168333000n),+32400s,2299161j)> 

d.to_s
=> "2019-02-20T15:15:30+09:00" 
# 一天前
(d - 1).to_s
=> "2019-02-19T15:15:30+09:00" 
# 一个小时前
(d - 1/24.0).to_s
=> "2019-02-20T14:15:30+09:00"  

DateTime 加减单位是天数, Time类加减单位是秒.

UTC时间

DateTime 类: DateTime.now.new_offset(0) Time 类: Time.now.utc

    DateTime.now.to_s
    => "2019-02-21T16:44:44+09:00" 
    DateTime.now.new_offset(0).to_s
    => "2019-02-21T07:46:30+00:00" 
    Time.now
    => 2019-02-21 16:46:33 +0900 
    Time.now.utc
    => 2019-02-21 07:46:44 UTC