Ruby Date and Time

Ruby Date and Time

Create the current date and time

Here's a simple example of getting the current date and time:

This results in the following:

Current Time : Mon Jun 02 12:02:39 -0700 2008
Current Time : Mon Jun 02 12:02:39 -0700 2008

Get the Date and Time component

We can use time objects to get components of various dates and times. Take a look at the following example:

#!/usr/bin/ruby -w
# -*- coding: UTF-8 -*-

time = Time.new

# Time 的组件
puts "当前时间 : " + time.inspect
puts time.year    # => 日期的年份
puts time.month   # => 日期的月份（1 到 12）
puts time.day     # => 一个月中的第几天（1 到 31）
puts time.wday    # => 一周中的星期几（0 是星期日）
puts time.yday    # => 365：一年中的第几天
puts time.hour    # => 23：24 小时制
puts time.min     # => 59
puts time.sec     # => 59
puts time.usec    # => 999999：微秒
puts time.zone    # => "UTC"：时区名称

This results in the following:

当前时间 : 2015-09-17 15:24:44 +0800
2015
9
17
4
260
15
24
44
921519
CST

Time.utc, Time.gm, and Time.local functions

These functions can be used to format standard format dates, as follows:

# July 8, 2008
Time.local(2008, 7, 8)  
# July 8, 2008, 09:10am，本地时间
Time.local(2008, 7, 8, 9, 10)   
# July 8, 2008, 09:10 UTC
Time.utc(2008, 7, 8, 9, 10)  
# July 8, 2008, 09:10:11 GMT （与 UTC 相同）
Time.gm(2008, 7, 8, 9, 10, 11)  

The following example gets all the components in the array:

[sec,min,hour,day,month,year,wday,yday,isdst,zone]

Try the following example:

#!/usr/bin/ruby -w

time = Time.new

values = time.to_a
p values

The above instance runs the output as:

[39, 25, 15, 17, 9, 2015, 4, 260, false, "CST"]

The array can be passed to the Time.utc or Time.local function to get the different formats of the date, as follows:

#!/usr/bin/ruby -w

time = Time.new

values = time.to_a
puts Time.utc(*values)

The above instance runs the output as:

2015-09-17 15:26:09 UTC

Here's how to get time, the number of seconds since the era (platform-related):

# 返回从纪元以来的秒数
time = Time.now.to_i  

# 把秒数转换为 Time 对象
Time.at(time)

# 返回从纪元以来的秒数，包含微妙
time = Time.now.to_f

Time zone and daylight saving time

You can use the Time object to get all the information about time zones and daylight saving time, as follows:

time = Time.new

# 这里是解释
time.zone       # => "UTC"：返回时区
time.utc_offset # => 0：UTC 是相对于 UTC 的 0 秒偏移
time.zone       # => "PST"（或其他时区）
time.isdst      # => false：如果 UTC 没有 DST（夏令时）
time.utc?       # => true：如果在 UTC 时区
time.localtime  # 转换为本地时区
time.gmtime     # 转换回 UTC
time.getlocal   # 返回本地区中的一个新的 Time 对象
time.getutc     # 返回 UTC 中的一个新的 Time 对象

Format the time and date

There are several ways to format dates and times. The following example demonstrates some of them:

#!/usr/bin/ruby -w
time = Time.new

puts time.to_s
puts time.ctime
puts time.localtime
puts time.strftime("%Y-%m-%d %H:%M:%S")

The above instance runs the output as:

2015-09-17 15:26:42 +0800
Thu Sep 17 15:26:42 2015
2015-09-17 15:26:42 +0800
2015-09-17 15:26:42

Time format instructions

The instructions listed in the following table are used with the method Time.strftime.

Time algorithm

You can spend time doing some simple arithmetic, as follows:

now = Time.now           # 当前时间
puts now

past = now - 10          # 10 秒之前。Time - number => Time
puts past

future = now + 10        # 从现在开始 10 秒之后。Time + number => Time
puts future

diff = future - now      # => 10  Time - Time => 秒数
puts diff

This results in the following:

Thu Aug 01 20:57:05 -0700 2013
Thu Aug 01 20:56:55 -0700 2013
Thu Aug 01 20:57:15 -0700 2013
10.0